HYDRAULIC PRESS

This press was invented and introduced to the public by Mr. Joseph Bramah, of Piccadilly, Engineer. Mr. W. Nicholson, in his Journal of Natural Philosophy, Chemistry, and the Arts, vol. 1. April, 1797, gave an account of it, with engravings, from which the following observations are extracted, which will give a brief description of this powerful machine, that is superseding the common book press with a screw in all extensive establishments.

“Its action is as follows: when the lever or pump handle is raised, it brings up the piston, which would leave a vacuum beneath if the pressure of the atmosphere did not force the water in through a side valve. The lever is then to be pressed down, which causes the side valve to shut, and forces the water through a valve at the bottom, whence it passes through a pipe into the cavity of the great cylinder, and raises the piston or pressing rammer. A repetition of the same process forces more water in, and the pressure may in this manner be carried to a great extent.

“There is no difficulty in computing the force of this instrument. If the diameter of the pump barrel be one quarter of an inch, and that of the cylinder one inch, that is to say, four quarters of an inch; one pound lodged upon the piston rod of the pump will be in equilibrio with sixteen pounds lodged upon the table of the press; the weights of the parts of the engine attached to, and moving with each piston, being respectively included. And if the length of the pump lever be fifteen inches, and the distance between the centres of motion and of action be two inches, one pound at the end of the lever will gain an advantage of 7½ times when compared with that at the piston rod. Instead, therefore, of sixteen pounds upon the table being equal in effect to counterpoise this last action, there will be required upwards of 120 pounds. But a man in this action of pumping by a downward pressure, can without difficulty apply his whole weight, and with great ease one third or one fourth of his weight, suppose 50 pounds. In this case the pressure will be equivalent to fifty times 120 pounds, or 6000 pounds, that is to say, nearly three tons.

“To compare this engine with a screw, in theory, we must enquire what fineness of thread and length of lever would afford a purchase of 120 to one. Let us suppose the thread of a screw, substituted in the place of the cylinder, to be one tenth of an inch thick; the distance from the top of one thread to the top of the next will in this case be one fifth of an inch. This is the space through which the weight must rise in one revolution. The power must therefore move through 120 times that space, namely twenty-five inches; but a lever or radius four inches long will describe a circle somewhat larger than this, and consequently such an engine would in theory be equal in power to the hydraulic engine we have been contemplating.

“But when the subject is viewed practically, the difference between the two engines appears to be very remarkable. All practical men know how very large a part of the force operating by means of engines is employed in overcoming frictions. Every one is aware of the extreme friction between solids, and the very slight friction which takes place between the parts of fluids. This is seen in the common expedient of oiling the pivots of wheels, and in the very gradual decay of motion in fluid bodies; while solids moving on each other stop at once, as soon as the force is diminished to a certain degree. The screw is an organ peculiarly liable to friction, and this friction is always much greater than the whole of the reacting force; for there are few instances where a screw will return from extreme pressure, when the agency upon the lever is withdrawn. It is also to be considered, that the whole force of the weight or resistance acts directly upon the face of the screw, at which the motion is required to take place. It has not been appreciated in what degree this resistance or friction increases with the weight. In lighter actions the simple ratio has been inferred; but under more severe pressures the two metallic faces extrude the greater part of the half-fluid matter between them, and appear, by the magnitude of their resistance, to be attached to each other by a process of the nature of cohesive attraction. For these and other reasons, it appears nearly impracticable to form any comparison between two engines so different in principle, but such as shall be deduced from immediate experiment of their effects. I am not in possession of numerical data to indicate the actual power of screw-engines or presses; which are perhaps the less necessary, because those who are the most interested in the success of an improvement like the present, are for the most part able to come at these without difficulty.

“In an engine of this kind, the diameter of the great piston was four inches, and of the smaller three-eighths of an inch; and the advantage given by the lever or handle was twelve to one. Above the piston of the great cylinder was applied a long lever, at one end of which was an axis, and at the other end a large scale to hold weights; it contained twenty hundred weight. The distance between the axis of motion of this lever and the part where it acted on the piston was six inches; and the distance from the same axis to the extremity where the scale was hung was 126 inches. Every hundred weight in the scale consequently pressed upon the piston with a force equal to twenty-one hundred weight; whence the whole pressure was twenty-one tons. It was easy to work the lever briskly with one hand, and each stroke raised the scale near one-third of an inch. Forty-seven pounds hung at the end of the lever, carried it down with a moderate swiftness of working; but a weight of only forty-three pounds remained in equilibrio, and did not descend. Now, as the true weight in theory was thirty-two pounds, it follows that less than one-third of the actual power was employed to give velocity and overcome all friction.

“It may be remarked, that the principal frictions in these machines must be at the circumference of the pistons, and that these do not increase in the simple, but in less than the subduplicate, ratio of the power. For if the diameter of the great cylinder were double, every thing else remaining unchanged, the surface of its piston, and consequently the power, would be quadrupled. But the friction would be only doubled, and that merely at the leathering of the greater piston.

“As the pressure in the experiment last mentioned amounted to 47·040 pounds upon the great piston of four inches in diameter, or sixteen circular inches surface, it amounted to 2940 pounds upon each round inch. But the medium pressure of the atmosphere on a round inch is near twelve pounds, consequently the action was equal to 245 atmospheres: and as each of these corresponds with a column of 34 feet of fresh water at a medium, the water in the cylinder was pressed in the same manner as if the whole column had been 8330 feet, or 1⅔ mile, long.

“Large presses of this construction are made with two pumps of 1¼ inch bore, and a cylinder of seven inches. These have been used in pressing hay and cotton for package; and, as I am informed, are effective in producing a greater condensation on the material with a much less application of moving power and consumption of time.”

The following description and figures are taken from Dr. Ure’s Dictionary of Arts, Manufactures and Mines, 8vo. 1839.

Fig. 1. Fig. 2.

“The framing consists of two stout cast-iron plates a, b, which are strengthened by projecting ribs, not seen in the section, fig. 1. The top or crown plate b, and the base plate a, are bound most firmly together by four cylinders of the best wrought iron, c, c, which pass up through holes near the ends of the said plates, and are fast wedged in them. The flat pieces e, e, are screwed to the ends of the crown and base plates, so as to bind the columns laterally. f is the hollow cylinder of the press, which, as well as the ram g, is made of cast iron. The upper part of the cavity of the cylinder is cast narrow, but is truly and smoothly rounded at the boring-mill, so as to fit pretty closely round a well-turned ram or piston; the under part of it is left somewhat wider in the casting. A stout cup of leather, perforated in the middle, is put upon the ram, and serves as a valve to render the neck of the cylinder perfectly water-tight, by filling up the space between it and the ram; and since the mouth of the cup is turned downwards, the greater the pressure of water upwards, the more forcibly are the edges of the leather valve pressed against the inside of the cylinder, and the tighter does the joint become. This was Bramah’s beautiful invention.

“Upon the top of the ram, the press-plate or table h, strengthened with projecting ridges, rests, which is commonly called the follower, because it follows the ram closely in its descent. This plate has a half-round hole at each of its four corners, corresponding to the shape of the four iron columns along which it glides in its up-and-down motions of compression and relaxation.

Fig. 3. Fig. 4.

“k, k, figs. 1. and 2., is the framing of a force pump with a narrow barrel; i is the well for containing water to supply the pump. To spare room in the engraving, the pump is set close to the press, but it may be removed to any convenient distance by lengthening the water-pipe u, which connects the discharge of the force pump with the inside of the cylinder of the press. Fig. 3. is a section of the pump and its valves. The pump m, is of bronze; the suction-pipe n, has a conical valve with a long tail; the solid piston or plunger p, is smaller than the barrel in which it plays, and passes at its top through a stuffing-box q; r is the pressure-valve, s is the safety-valve, which, in fig. 2., is seen to be loaded with a weighted lever; t is the discharge-valve, for letting the water escape, from the cylinder beneath the ram, back into the well. See the winding passages in fig. 4. u is the tube which conveys the water from the pump into the press-cylinder. In fig. 2. two centres of motion for the pump-lever are shown. By shifting the bolt into the centre nearest the pump-rod, the mechanical advantage of the workman may be doubled. Two pumps are generally mounted in one frame for one hydraulic press; the larger to give a rapid motion to the ram at the beginning, when the resistance is small; the smaller to give a slower but more powerful impulsion, when the resistance is much increased. A pressure of 500 tons may be obtained from a well-made hydraulic press with a ten-inch ram, and a two and a one inch set of pumps.”

In a Report addressed to the Commissioners of Her Majesty’s Woods, Forests, &c., in July 1839, as the result of an inquiry with reference to the selection of stone for building the new Houses of Parliament, it is stated the experiments relating to the cohesive strength of the stones, or their resistance to pressure, were made at the manufactory of Messrs. Bramah and Robinson, with a six-inch hydraulic press, the pump of which was one inch in diameter. According to trials previously made by Messrs. Bramah and Robinson, one pound weight at the end of the pump lever produced a pressure on the face of the cube [two inches square] equal to 2·53 cwt., or to 71·06 lbs. on the square inch; from this datum it may be estimated how immense the pressure is that can be obtained by this press, when the strength of a man is exerted at the pump. I have used the common book press with an iron screw to press printed paper, and I have also used a Hydraulic press of an estimated power of eighty tons: besides the greater expedition in pumping this press up than screwing the other down, I can state from my own observation, that the hydraulic press produced as great an effect upon the paper in three hours as the screw press did in a night, or at least fourteen hours. This may show the great superiority of this press over that which has been in general use in printing offices. The hydraulic press has fully accomplished in practice all that was expected from it, and has established for itself a high character, which it richly deserves.

Fig. 1. Fig. 2.

Fig. 3. Fig. 4.


hydrochloric acid

A strong, corrosive, inorganic acid (HCl), manufactured by absorbing hydrogen chloride in water. It is one of the most corrosive of acids, and is particularly destructive to cellulose, breaking the cellulose chain into even smaller units, resulting ultimately in its complete hydrolysis.

The problems with hydrochloric acid began with the use of chlorine in bleaching paper fibers. For many years thereafter, the chlorine substances were insufficiently removed by washing, giving rise to the formation of the acid in paper. Although washing techniques have improved, excess residual hydrochloric acid can exist in paper because of the practice of using chlorine compounds to wash and bleach paper subsequent to its manufacture.

Bookbinding and the Conservation of Books: A Dictionary of Descriptive Terminology

US Government publication (Library of Congress), published openly in electronic edition by CoOL. Not a Gutenberg/pre-1930 public-domain text -- verify rights before reprinting rather than quoting.


hydrogel

A gel in which the liquid is water.


hydrogen cyanide

An extremely toxic, colorless liquid (HCN), prepared by reacting methane, air, and ammonia over a platinum catalyst at 1,000° C. It is used to fumigate books.


hydrogen peroxide

An oxidizing chemical (H2O2), which can be prepared from barium peroxide and dilute sulfuric acid. It is used in bleaching paper pulp, sometimes alone, but more often in combination with other pulp bleaching agents.


hydrogen-ion concentration

The concentration of hydrogen ions (more properly hydronium ions—H3O+, although its true structure is probably (H,4H2O), existing in an aqueous solution. It is a measure of the active acidity or basicity and is expressed metrically as the number of moles or gram-formula weights (1.0078 g.) of hydrogen ions (H+) per liter of solution. The hydrogen-ion concentration of a solution may also be expressed in terms of its pH, which is defined as the negative logarithm to the base ten of the hydrogen-ion concentration. In aqueous solutions, neutrality is the condition that exists when the concentration of hydrogen ions and hydroxyl ions are equal. At 25° C., neutrality occurs at a pH of 7.0, which is the pH value of pure (distilled) water when condensed hot and shielded from contact with atmospheric carbon dioxide.

Measurement of hydrogen-ion concentration, or pH, may be made colorimetrically, by means of the proper use of suitable neutralization indicators, or, more accurately, by potentiometric methods employing any of various electrodes, which exhibit the proper specificity for hydrogen ions.

Hydrogen-ion concentration is important in archival work because it has been adequately demonstrated that the presence of acid(s) in ink, leather, paper, etc., has or can have, a deleterious effect on such materials, the extent of the effect depending not so much on the volume of acid present, as on the type of acid and its concentration, i.e., a large volume of a relatively weak organic acid, such as formic acid, is less harmful than a smaller amount of a powerful, inorganic acid, such as sulfuric acid. As a decrease of pH means a logarithmic increase in acid concentration, levels of concentration below pH 5.0, or under certain circumstances, even 6.0, become important. Conversely, although not as serious a problem, a high concentration of hydroxyl ions, corresponding to a pH of 10.0 or above, can lead to serious oxydization of cellulosic materials.

The increase in hydrogen-ion concentration as pH declines is given be

pH      moles/ liter

7.0     0.0000001

6.0      .000001

5.0      .00001

4.0      .0001

3.0      .001

2.0      .01

1.0      .1

0.0     1.0

See also:ACID; ALKALI.

American Paper and Pulp Association. The dictionary of paper, including pulp, paperboard, paper properties and related papermaking terms. 3rd ed. New York. American Paper and Pulp Association. 1965.

Kingzett, Charles Thomas. Kingzett's chemical encyclopedia; a digest of chemistry & its industrial applications. Ed. by D. H. Hey, and others. 9th ed. London. Baillière, Tindell and Cassell. 1966.

Miall, Laurence Mackenzie, and D. W. A. Sharp, eds. A new dictionary of chemistry. 4th ed. New York. Wiley. 1968.


hydrolysis

In its broadest sense, hydrolysis indicates a reaction between any substance and water; however, the use of the term is commonly restricted to those reactions due directly to the hydrogen and hydroxyl ions of the water. Due to hydrolysis, for example, nearly every salt yields a slightly acid or alkaline solution. Thus, ethyl acetate in water, for example, forms acetic acid and ethanol: CH3CO2C2H5, + H2O  → CH3MCOOH + C2H5OH.

Hydrolysis is the basis for the manufacture of soap (saponification), whereby fats (glycerol esters of fatty acids) are split with aqueous solutions of sodium hydroxide to form the sodium salt of the fatty acid (soap) and the alcohol (glycerol—more commonly known as glycerine). In reactions involving sal[s, the neutralization reaction that led to the formation of the salt is partially reversed, forming some free acid and free alkali. If the acid is weak, i.e., poorly ionized, and the alkali is strong, i.e., highly ionized, the aqueous solution of the salt will have an alkaline reaction as a result of the hydrolysis.

In the opposite case, that of a strong acid and weak base, the salt will have an acidic reaction in an aqueous solution. An example of the latter is papermaker's alum (aluminum sulfate), which is hydrolyzed in aqueous solution to form aluminum hydroxide (Al(OH)), which is insoluble and therefore forms few ions, and sulfuric acid (H2SO4), which is almost completely ionized in a dilute water solution. The acid character of alum is well known by its extremely sour, astringent taste, and by its detrimental effect on the permanence of paper.


hydrophilic

A substance that is readily wetted by water. VELLUM is a typical hydrophilic substance.


hydrophobic

A substance that is water repellent, or not easily wetted by water. Nylon is a typical hydrophobic substance.


hygroexpansivity

A change in the dimensions of a material, such as paper, because of a change in the ambient relative humidity of the atmosphere surrounding the material. The phenomenon is usually expressed as a percentage, and is generally several times greater in the cross direction of a paper than in the MACHINE DIRECTION, because paper fibers expand much more in diameter than in length when wetted. Hygroexpansivity is of considerable importance where the dimension of paper is critical, such as in multi-color offset printing. See also: ANISOTROPIC BEHAVIOR; DRIED-IN STRAIN.

Casey, James P. Pulp and pa per: chemistry and chemical technology. 2nd ed. New York. Interscience. 1960-61. 3 vol.


hygrometer

An instrument used for measuring the relative humidity, or percentage of moisture saturation of the air, such as the dew-point hygrometer, psychrometer, hair hygrometer, etc.


hygroscopic moisture

The amount of moisture retained by a material in the AIR DRY condition.


hygroscopicity

That property of a substance which enables it to absorb water vapor from the surrounding atmosphere. Relative to most materials, vellum and paper, particularly the former, are strongly hygroscopic.


hymnal style

A style of binding used for church hymnals, or similar publications which utilizes a narrow leather spine, cloth sides, round or square corners, and colored edges.

Philip, Alexander John. The business of bookbinding for librarians …Gravesend. A. J. Philip. 1935.


HYPHEN

A hyphen, marked thus (-), is employed in connecting compounded words; as, “Lap-dog, tea-pot, pre-existence, self-love, to-morrow, mother-in-law.”

It is also used when a word is divided, and the former part is written or printed at the end of one line, and the latter part at the beginning of another. In this case, it is placed at the end of the first line, not at the beginning of the second.—Murray.

Public domain (Project Gutenberg, pre-1930 text)


hysteresis

The differential value of a property, contingent upon approaching a known value of a related condition from a higher or lower level. A material such as paper, for example, that is to be conditioned at 50% relative humidity, will contain more moisture when this level is approached from above 50% than when approached from below. Hysteresis has a considerable influence in governing the dimensional stability of paper. <!-- BEGIN I -->


I

The Roman equivalent of 1. See: ROMAN NUMERALS.


ichthyocoll

See: ISINGLASS.


IDENTIGRAPHY

The Dutch papers in 1825 mentioned a new discovery in printing, to which the inventor gave the name of Identigraphy. It consists in a new application of the art of lithography, by which a reprint of common letterpress is obtained in a very short time; the inventor undertaking to reprint the foreign journals within two hours after their arrival by the mail.

Illuminator. See Fac.


illuminated

A manuscript or book embellished with ornamental letters, scrolls, miniature and/or other designs, usually in gold and red, but also in silver and other colors.

Holden, John Allen. The bookman's glossary…3rd ed. New York. Bowker. 1951.


illuminated binding

A binding which has extra colors in its scheme of decoration, and especially a binding in which a design was first blocked in blind and afterwards colored. Originally a French innovation, this style was used in England from about 1830 to 1860. Burnt sienna, carmine, gamboge, indigo, sap green and ultramarine were the colors most often used mainly because they were more lightfast. The color was mixed with a suitable gum and applied to the cover; when it was dry, gold leaf was laid on the areas to be gilded, and the entire design was then impressed with the heated block, which fixed both gold and colors, sharpening the edge of the latter.

Hannett, John. Bibliopegia; or, the art of bookbinding… London. Simkim, Marshall. 1848.

Harrod, Leonard Montague. The librarians' glossary of terms used in librarianship and the book crafts, and reference book. 3rd ed. London. Deutsch. 1971.

Middleton, Bernard C. A history of English craft bookbinding technique. New York. Hafner. 1963.

Winans, Leonard G. The book from manuscript to market. New 370. York. Grosset 8 Dunlap. 1941.


illumination

The decoration of a manuscript or book with painted pictures, ornamented letters, designs, or a combination thereof, in colors and (usually) burnished gold or silver.

The design was first drawn and then sized with a mixture of clay, gypsum or lime, followed by an adhesive (glair). The gold or silver leaf was laid on and burnished, and the colors were then applied.

Although illumination is considered to be a medieval art, its origins can be traced back to illustrated Egyptian papyrus rolls and especially to Greco-Roman book illustration. Classical artists illustrated the text of codices with continuous chronological sequences of scenes, which often filled the entire page.

The word "miniature," which comes from the Latin minimum (red lead, which the Romans used for initial letters), is frequently used with reference to the individual pictures in an illuminated work; however, a "miniature painting" is not synonymous with "illustration," because illuminations are usually executed in gold or silver while miniatures generally are not.

Glaister, Geoffrey Ashall. An encyclopedia of the book. Cleveland. World. 1960.


illustration board

A board used primarily for the application of ink and water color. It is made by pasting drawing paper to one or both sides of a board, one that is usually filled, pulp-lined, or pasted. The usual properties of the drawing paper, such as finish and sizing, are essential, but hard sizing and good erasing quality are of greatest importance. The finished board should be as free as possible from warping. The basis weight is ] 50 pounds (] 7 x 22—500), and the thickness is 0.0325 inch.


imbrication

A form of embellishment of a book featuring a pattern consisting of overlapping leaves or scales. The term is also applied to any decorative pattern composed of overlapping elements.

Mayer, Ralph. A dictionary of art terms and techniques. New York. Crowell. 1969.


imitation art paper

A printing paper containing a high percentage of china clay, kaolin, etc., in the paper furnish. It has a very high water finish, which provides the required surface opacity, and absorbency suitable for the printing of some halftones. Imitation art paper differs from ART PAPER (1) in that the clay is mixed with the fibers, and is thus an entirely on-machine operation. Coated art paper, which is the superior product, may be determined by the black mark which results from rubbing it with a silver coin. Imitation art paper is not usually suitable for halftone printing where the screen is finer than ]33 lines.

British Federation of Master Printers. Preliminary technical course in printing. London. British Federation of Master Printers. 1967. 7 vol.


imitation cloth

A material other than a woven fabric, e.g., paper or plastic, which has been embossed to give it the surface appearance of a fabric.

Cunha, George Daniel Martin. Conservation of library materials. Metuchen, N.J. Scarecrow. 1967.


imitation gold

A metallic composition used as a substitute for gold leaf or foil in the lettering and decorating of books, particularly in edition binding. It is usually made of powdered bronze. It lacks the richness and depth of genuine gold and eventually tarnishes due to oxidation. Also called "artificial gold."

Groome, George C. Bookbinding materials. Washington, D.C. U.S. Government Printing Office. 1938.

Hitchcock, Frederick H. The building of a book…2nd ed. New York. Bowker. 1929.


imitation leather

A coated fabric, rubber or plastic composition, or absorbent paper, manufactured so as to resemble genuine leather. Of the many efforts to find a satisfactory substitute for leather, both proposed and actually manufactured, only a few have any extensive use in bookbinding today, and, as they usually contain cellulose nitrate or polychlorides, their permanence is suspect. Also called "artificial leather."

Langwell, William Herbert. The conservation of books and documents. London. Pitman. 1957

Pleger, John J. Bookbinding. Rev. ed. Chicago. Inland Printer. 1924.


imitation parchment

A type of relatively strong paper first produced by W. E. Gaine in 1857. It is made entirely of chemical wood pulp and is called imitation parchment in order to distinguish it from parchment paper made in imitation of true (animal) parchment. Imitation parchment now bears little resemblance to that paper, nor does it possess any of its qualities. The paper may be rendered partially transparent, greaseproof, and somewhat waterproof by prolonged beating (hydration) of the pulp or by treating the paper with sulfuric acid. The usual basis weight is 30 pounds (24 X 35—500).

American Paper and Pulp Association. The dictionary of paper, including pulp, paperboard, paper properties and related papermaking terms. 3rd ed. New York. American Paper and Pulp Association. 1965.


imitation Russia

A vegetable-tanned split cowhide finished with oil of birch to impart the odor characteristic of true RUSSIA LEATHER.


imitation vellum

A paper made so as to simulate true VELLUM, and produced in much the same manner as IMITATION PARCHMENT, except that it is thicker.


imperfect

1. A book having leaves or sections omitted, duplicated, misplaced or bound in upside down, damaged, etc. 2. An obsolete term for reams of paper that have not been made up of the full number of a printer's ream.

Cockerell, Douglas. Bookbinding, and the care of books; a textbook for bookbinders and librarians. 5th ed. London. Pitman. 1971.


IMPERFECT PAPER

Paper sent into a printing office to print upon, without the extra quantity which partly constitutes perfect paper; thus a ream of imperfect paper consists of twenty quires of twenty-four sheets each, which makes a ream containing 480 sheets; in this state it is termed inside quires: sometimes, but rarely, it is sent in with the outside quires, in which case there are not so many sheets in a ream. See Paper; also Perfect Paper.

Imperial Press. See Sherwin and Cope’s Press.


imperfection note

The bookbinder's list of shortages encountered as he proceeds through to the end of an edition run. Certain sections or plates may be missing because of spoilage or short printing, and it is customary to print the requisite extra copies of these when, and if, the book is reprinted.

Simon, Oliver. Introduction to typography. 2nd ed. London. Faber and Faber. 1963.


imperfections

1. Printed sheets rejected by the binder because of some kind of imperfection, and which must be replaced before the work can be completed. 2. Additional sections, i.e., those printed and folded in excess of the number required to complete the run.

U.S. Government Printing Office. Theory and practice of bookbinding. Rev. ed. Washington, D.C. U.S. Government Printing Office. 1962.


IMPERFECTIONS

Books.—In gathering books, when one sheet is off, the surplus of the other sheets is called Imperfections.—M.

We now call this surplus the Waste: and after the work is delivered, or is in a state of delivery, and the bookbinder, or any person in whose possession the book may be, discovers that a sheet, or part of a sheet, or a plate, or any part whatever, is wanting, to make the book complete, he applies for them; or he may apply to change a sheet that is either dirty or torn. These deficiencies, or defects, are now termed Imperfections. See Waste.

Letters.—When the founder has not cast a proportionable number of each sort of letter, the wanting letters are called Imperfections, as making the rest of the fount imperfect. See Sorts.—M.


imperfections

Sheets rejected on account of being in some respect imperfect, and for which others are required to make the work complete.


imperfections

sheets rejected by the binder and returned to the printer to be replaced.


imperial morocco cloth

A linen cloth finished with a grain pattern resembling leather, usually a straight-grained morocco.


imperial morocco cloth

A grain-finished linen-thread cloth manufactured by the Winterbottom Book Cloth Company of England. It is made in different colors; of these the library has tried but one, the green. On books which have some, but not constant use, it is a very good substitute for leather. It takes lettering well, and wears better than any of the cloths the library has tried. The price is 48 cents per square yard by the roll, fast color, duty paid. (De Jonge & Co., 69–73 Duane St., New York.)


Imposing

Arranging and locking up a form of type in a chase.

The American Printer: A Manual of Typography


IMPOSING STONE

The stone on which the compositor imposes and corrects his forms. It was formerly called the Correcting Stone.

Imposing stones are of different sizes to suit the business and the situation in which they are placed, as they require a good light. Some are made to hold two demy forms, others to hold three royals. The stone should be of a firm texture, and its upper surface smooth, so as not to wear the bottom of the types. Imposing stones are sometimes saturated with oil, to lessen the friction. Their height is about three feet, and the length of one calculated to contain two demy forms is five feet, and its width two feet two inches.

The frame on which the stone rests, is fitted up with drawers for furniture—one of these is for quoins, always the uppermost, one for side sticks and foot sticks, one for broad and narrow, and one for wider pieces;—these drawers are sometimes made of the whole width of the frame, so as to draw out on either side, and sometimes there are two within this width, one on each side.

Of late years, in some offices, cast iron has been substituted for stone, the upper surface of which has been turned flat and smooth in a lathe; and when a large size is wanted, two are attached together.

Impression holds out. See Holds out.—M.


IMPOSING STONE

The stone on which compositors impose and correct forms.


IMPOSING,

is the arrangement of the pages of a sheet, or of a form, in their proper order on the stone, and the wedging of them up in a chase, with a view to their being printed.

The knowledge of thus laying down pages, so that the sheets may fold correctly when printed, is of essential consequence to every compositor engaged on book work.

A workman would be held inexcusable who did not know how to lay down with accuracy all the common sizes; viz. quartos, octavos, and duodecimos: but even with this knowledge he is frequently at a loss when at work upon sizes that do not frequently occur; and more particularly so at the close of a volume where there are fragments, which are required to be imposed together, for the purpose of saving presswork and warehouse work.

A youth, who has just gone to the business, feels a natural pride in showing that he is making progress; and he wishes to improve himself without having continually to appeal to his instructor; but he does not possess the means.

The young man from the country, who has been educated in a house where there has not been much book work done, which is generally the case, and who, of course, is not very expert at his profession, when he comes to work in an extensive book house in town, feels his deficiency, and more particularly if he has to lay down his pages in a large companionship; he does not like to acknowledge his ignorance, nor to ask for information: he has consequently to work his way at a great disadvantage.

Under these circumstances it frequently happens that the pages are laid down wrong, which causes a great deal of trouble and loss of time in their rectification; and this trouble is considerably increased if the work be on a small type and solid. In this case, if the cords have been taken off, it is not advisable to transpose the pages without wetting them, for fear of breaking the matter, or at least squabbling it; the form has then to be dried, before the pressman can pull another proof.

All the works on Printing hitherto published, are deficient in giving a sufficient variety of tables for imposing, as a reference for the workman, as well as for the reader and the master printer. This deficiency of reference occasionally causes the compositor to re-impose his forms, as I just now observed, and also in many instances to cut up new furniture.

To remedy this inconvenience I have considerably exceeded the number of what has been given in any other work, by adding such tables as are likely to occur in practice, and to which there has hitherto been no reference.

I have given all the Tables of Imposition that are in Luckombe and in Stower, except a half-sheet of sixty-fours, although I disapprove of the arrangement of the pages in many of them, from their not cutting up or folding in the most convenient manner; yet, as they have been acted on in a great number of instances, I would not reject them, it being advisable in reprints to preserve uniformity, which may enable the proprietor to make up a few more copies from the waste of both editions. I have added several, in which I think there is an improvement in these particulars.

I have also endeavoured to make each size complete, by giving a sheet, a half sheet, a quarter of a sheet, and the usual fragments that occur; varying the arrangement of the pages in a great number of instances, to suit the different ways of folding the paper.

The whole of the signatures in each form are given, that they may serve as a guide in laying down the pages, particularly where there are a great number in a sheet; they might then all be taken out, if thought proper, except the first, and the first in the offcut, which are the only ones I would retain, and all that are necessary, the others causing the bottoms of the pages to look unsightly; for the person who folds the sheets has only to keep the signature at the outside, and the pages must be folded right.

When works are in half sheets, it is advantageous to work two together, as it enables the bookseller to deliver a single copy in sheets without cutting up the back; and also at the conclusion of a work that is in sheets where there are two half sheets, as it saves time and trouble in the warehouse; it not being necessary to divide the sheet and insert a half in each volume, but the whole sheet may be gathered in the volume to which either of the signatures belongs; by which means there will be fewer mistakes, and fewer imperfections required.

When we arrive at a great number of pages in a sheet, they resolve themselves into the same order as quartos, octavos, and duodecimos; and in these cases I have repeated the imposition rather than refer to another size, which is not always very clearly understood when two, three, or more sheets are combined. Upon this principle I have repeated the half sheets, quarter sheets, and fragments, so as to make each size complete in itself.

It is usual when a fragment at the end of a volume makes six pages to impose it as eight: in this case there are two blank pages. Sometimes the author fills these up, by adding to the text; at other times the bookseller occupies them with advertisements of other publications in which he is interested.

When a compositor lays down his pages, it might prevent mistakes if he looked over them to see that they were right before he untied the page cords; and it is a good check to examine the folios of every two adjoining pages in a quarter, to see that their sum makes one more than the number of pages in the sheet, or half sheet: thus, in a sheet of folio, 1 and 4, equal to 5, are imposed together; in a quarto, 1 and 8; in an octavo, 1 and 16; in a duodecimo, 1 and 24; in sixteens, 1 and 32; in eighteens, 1 and 36; and so in every other size: and this combination continues through all the other adjoining pages, according to the order in which they lie on the stone, calling the first page in the sheet 1, the second 2, and so on in succession.

The short cross is always better in the middle of the chase, if the margin will allow it; as it divides the matter more equally, and the form is safer when it is locked up.

If it be the first sheet of a work that is to be imposed, or it be found necessary to increase the number of sheets in chase, the compositor applies to the overseer, or to the person who has the care of the materials, for a pair of chases.

The pages being laid upon the stone in their proper order, and as near the required distance from each other as can be determined by the eye, the compositor then places his chases; he takes one with both hands and lays the off side or end, as it may be, on the stone at the outer side of his pages, and lowers the near side gradually, till it lies flat on the stone, taking care that the inner edges of the chase and the cross bars do not rest on the face of the pages to injure them, and that the grooves in the short cross are upwards.

The furniture has now to be cut for the sheet; but previous to doing this it is necessary to ascertain what kinds of it will be wanted, by trying the margin with a sheet of paper of the work, otherwise a great risk is run of cutting an expensive article to waste, and of incurring also a loss of time, both of which should be avoided if possible. The manner of making margin will be explained under its proper head. See Margin.

I would recommend that the headsticks in octavos should be in two pieces, each of them a little longer than the page is wide; this will allow the gutters to be a little longer than the page, so that they will come close to the footsticks at the bottom, and at the other end will go between the headsticks, thus securing the inside of the two pages, without any risk of the gutters binding when locked up, which they are apt to do when cut to the precise length of the page, as is the custom when the headsticks for each quarter are in one piece. The gutters thus being equal to about three picas more in length than the page, will answer for other works where the page is of the same width, but different in length.

The headsticks and gutters being arranged, the compositor will cut his backs a little longer than the page, and these abutting against the headsticks that project beyond the page towards the cross, will secure that side. The sidesticks should be of the full length of the page, and abut against the headsticks on the outside of the form. The footsticks may be a trifle shorter than the width of two pages and the gutter; for as there should always be a line of quadrats, or a reglet cut to measure, at the foot of each page, the footstick may be a pica shorter without danger, on this account, of any thing falling out, when the form is lifted, and it thus prevents the side and foot sticks from binding when locked up.

By cutting the furniture in this manner, the compositor will at once perceive that all his pages will be secure, and that the furniture cannot bind in any place when locked up. The gutter is pushed down to the footstick, and extends beyond the top of the pages; the two headsticks abut against the gutter, and project a little beyond the sides of their pages; the back is pushed up to the headstick, and extends a little below the bottom of the page; the footstick abuts against the back, and by being about a pica short prevents the sidestick from binding against it; and the sidestick abuts against the head, and extends the full length of the page: neither is there any impediment to driving the quoins.

I would never cut the heads and the backs of such a length as to project beyond the side and foot sticks; for when they do, they are in the way of the shooting stick, if a quoin has been driven close up, when the form has to be unlocked. Neither should the headstick project so much as the thickness of the back; nor the extra length of the gutter be so much as the headstick; otherwise they will bind and prevent the form from rising.

When the sidestick or footstick is so long as to project one beyond the other, it prevents the quoin from passing, and in unlocking causes a great deal of trouble to get it out; I have, in such cases, frequently seen the sidestick broken or spoiled in the attempt, and a page squabbled or broken. This arises from carelessness or idleness, both which generally cause more trouble ultimately than if the work were properly performed in the first instance. If it be thought unnecessary or wasteful to cut down side or foot sticks for a job, or a pamphlet, when there are none of a proper length in the house, a piece of furniture taken out of the drawer of the proper length and width, and placed inside next the page, will remedy the inconvenience, and cause the quoin to be driven with ease.

When placing the furniture about the pages leave the ends of the page cords out, so that they may be easily taken off, without the necessity of disturbing the pages to find the end, which will be the case if they be tucked in.

The furniture being now round the pages, I would recommend to the compositor to put some quoins round the form, not with any particular care that they fit, but merely to secure the pages, and by their means to push them up close to the heads, backs, and gutters.

After having taken a page cord from a page push up that page close to the furniture at the back and head, by means of the side and foot stick, to prevent the letters at the ends of the lines from falling down, and also tighten the quoins gently with your fingers.

All the page cords being taken off, and the pages pushed up close at the sides and heads, it will next be necessary to examine particularly that the margin be right; as also to put one or two scaleboards in all the backs and the heads between the furniture and the crosses. These scaleboards enable the pressmen to make register if there be any inequality in the furniture or the crosses, by changing their situations, or taking some of them away; they also enable the compositor to make the distance between the pages in the backs and heads uniform, which should always be the case; and no form of book work that has to be printed on both sides of the paper should ever be imposed without them. But scaleboard is never used in the gutters.

The form has now to be quoined, which many compositors are in the habit of doing very carelessly, thinking that if the form lifts it is quite sufficient. This is an erroneous opinion, and frequently causes errors from the slovenly manner in which the quoining is done, letters and even lines dropping out when the form is laid on the press, or taken off, which do not always get replaced correctly; and the pages are more likely to fall out if they stand a few days at the end of a bulk. As I have previously described the imposing of an octavo, I shall continue my observations with respect to that size, but the principle is the same whatever the size may be. I would have two quoins for each sidestick, not put in indiscriminately, but the furthest quoin when driven tight, to be about three quarters of an inch from the broad end of the sidestick, which will allow room for the shooting stick in unlocking, as also for the form being tightened if the furniture shrinks; and the other quoin when driven tight to be its whole length fairly within the sidestick, because this end of the stick being thin, will be liable to spring from the page if the quoin be driven far in, and thus leave the letters behind insecure, and in danger of falling out: I would have two for the footstick in the same situations, and a third in the middle to cover the end of the gutter. Each quarter, of a form of octavo, thus quoined, will be perfectly secure when the quoins are driven tight, provided the pages be made up to the same length, and the lines properly justified; should this not be the case, the compositor will be obliged to vary the quoining, to meet the evil of bad workmanship.

Before he tightens his quoins he examines whether the pages in the same quarter be of equal length, which he does by pressing against the footstick with his thumbs, and raising it a little from the stone; if it lifts up with it equally the ends of both the pages against which it presses, he is satisfied they are right, and tries the other quarters in the same manner; if he finds any of the pages short, he examines them to find out where the deficiency is and supplies it; sometimes a lead is wanting, sometimes a line. This will arise occasionally from the carelessness of some compositors who will not take the trouble of cutting a gauge by which to make up their pages, but do it by counting the lines; they sometimes omit a line, sometimes have a line too much, and sometimes are equally incorrect with their leads: in other cases I have known gauges cut carelessly of an improper length, which causes the same evil; and it also occasionally arises from having the gauges of three or four different works cut on the same piece of reglet, and mistaking one for the other. See Gauge.

I should now push the quoins up all round with my fingers, to confine the pages slightly, and then plane the form down gently by striking the planer with the fist; if any letters stand up they are easily pressed down by this mode of proceeding, without injuring their face; after this is done, it is necessary to examine the sides of the pages, to see that no letters have slipped out of their places at the ends of the lines, which is frequently the case when pages which have been tied up have lain under the frame some time; it may also happen in taking the page cords off, particularly if they be knotted. Having examined the pages, and rectified any thing that was found amiss, which is easily done in this state of the form, I should gently tighten the quoins all round the form in an equal manner with the mallet and shooting stick, and then plane down, but not violently; if any letters stand up, from some substance being underneath, as a space, or a letter, or a bit of the page paper, which will sometimes get torn off and remain, it will be better to omit planing that part down for the present, as it would only injure the type and answer no good purpose: the quoins should then be driven as tight as is necessary, still doing it regularly and equally all round the form, when the form should be planed down again, which may be done with firmer blows than before, still omitting the part where the letters stand up.

The form may now be lifted from the stone at the front edge, just sufficient to allow the compositor to see whether it will rise or not, but not so high as that a letter would drop out; if it dances, it must be dropped down again upon the stone, and the lines tightened by thrusting the point of a bodkin between some of the words, and tightening the quoins; thus bad workmanship causes fudges, and in this case is never safe, for the letters are always in danger of being drawn out at press. But it may arise from a letter having slipped down at the end of a line: in this case the remedy is easy, to unlock the quarter and put the letter in its proper place; when this is done, and the form will rise, take the substance that was under it completely away, lay the form down again, loosen the quoins in that quarter, then plane it down, and lock it up as before directed.

The forms should now be brushed over with the letter brush, and taken to the proof press, and the pressman should be told to pull them,—In some houses the proof press is in the press room, in that case the compositor either calls out “Proof,” or asks, “Who’s in Proofs?” and then tells the party how it is to be pulled, First Proof, or Clean; sometimes the proof press is in the composing room, and the compositor either calls out “Proof” to them, or rings a bell, different houses having different customs in this respect.

I would always put the flat side of the furniture upwards, as it is more convenient for the pressmen, when it is necessary to place bearers on the frisket; since they operate better on this surface than on the hollow side, and can be placed on any part of it.

In my opinion it is preferable to have each part of the furniture in one piece, where it is practicable; as, for instance, the gutters, the backs, and the heads; which prevents the pieces from being transposed, and the margin from getting wrong: but sometimes pieces will be wanted of a width that is not equal to any regular size, and then two must be used.

To prevent as much as possible one piece of furniture from being mistaken for another in the hurry of business, I would cut all the gutters of one sheet of a precise length; so also would I do with the backs, as also with the heads; but each sort should be of a different length from that of the others;—thus, though all the gutters would be exactly of a length, yet would they be of a different length from that of the heads and backs, and so of the others; and thus they would be easily distinguished from each other, and mistakes would be prevented.

The sheet being now imposed, the stone must be cleared; the saw and saw block put in their places—the shears—the mallet, planer, and shooting stick—the surplus furniture—the scaleboard—the quoins—and every other article; for in most houses there is a fine for leaving a foul stone. The compositor will tie up his page cords, and if he has any companions will return to them their proportion.

In imposing a sheet from the furniture of one that has been worked off, in the regular process of business, there are certain circumstances to be attended to, which are frequently omitted:—The chase and furniture of one form should always be used for a similar form; that is, the chase and furniture of the outer form should be again used for an outer form, and the chase and furniture of the inner form should be again used for an inner form; they should also be put round the pages in the same order in which they were put about those of the preceding forms. For want of care or thought in these apparently trifling circumstances a great deal of trouble, inconvenience, and loss of time, are frequently incurred; for the register will be almost sure to be wrong when this is neglected, and then the forms must be unlocked, and the scaleboards changed, some of them having to be taken out, or fresh ones to be inserted, and this accompanied by a great deal of dissatisfaction.

I have found it to be a saving of time to be a little methodical in imposing; I take out my quoins and lay them on the adjoining pages in their regular order, then, after the chase has been put over the pages, and the furniture about them, there is no loss of time in replacing the quoins, or in finding the proper situation for each of them: the page cords are then taken off; the quoins tightened; the form planed down, &c., as detailed in the preceding paragraphs for imposing the first sheet of a work.

It should always be borne in mind that the quoins ought to be tightened regularly and uniformly round the form; for if one quarter be locked up at once before the quoins are tightened in the other quarters, the whole will be distorted, and the pressmen will have great difficulty in making register.

After the furniture has been taken from a form for the purpose of imposing another, it will be the means of preventing the matter for distribution from going into pie if the compositor tie a cord about each page; at least it may prevent an accident, and save him some trouble.

The chases for a sheet ought always to be in pairs; for if they be of different sizes, or the rims of different thickness, it causes the pressmen to lose time in making register, when both forms are worked at the same press, and often occasions the spoiling of two or three sheets of paper before that object is accomplished.

Before the compositor locks up his form, but after the pages are pushed up close to the backs and the heads, he should cut a gauge to fit exactly the intervals between the backs and the heads; and a sheet should never be carried into the press room for press, without the margin having been tried by this gauge to see that it is right, and to correct it, if it should be wrong: for as the pressmen have frequently occasion to alter the scaleboards in working the reiteration, this alteration will necessarily affect the furniture of the succeeding sheet. I have always used two small pieces of clean reglet, brevier or longprimer, and have cut them to the precise length; I wrote on both in ink the name of the work to prevent mistakes, as also the words ‘Back’ and ‘Head’ on each respectively; made a hole through them with my bodkin, tied them together with a piece of page cord, and hung them on a nail within my frame, so that they were always ready for use.

I shall now enumerate the tables of imposition in the following pages, and add observations where it may appear necessary, to make them as clear as it is in my power to do, not only to facilitate the operation, but in many instances to give information that may be of service; and in some cases to accommodate the bookbinder, who is seldom thought of in a printing office, but who, in my opinion, ought to be constantly considered: for I hold that the binding of a book should be always kept in view, as we are all anxious to see how our work looks when it is splendidly dressed by his skill; and it would consequently not be just if we did not do all in our power to accommodate him: stating this opinion will also show my reason for making some of the observations, as it is a point that has hitherto been neglected in all practical works on printing.

I shall also notice the errors, where they occur, of my predecessors, not for the sake of finding fault, or of depreciating their labours, but to save trouble to the workman; for, by some unaccountable cause, wherever Luckombe has made a mistake, or committed an error, it has been copied by subsequent writers, who do not appear to have examined his arrangement of the pages, but to have taken it for granted they were right, and have thus continued his errors.

The writers since Smith have not, I think, reasoned correctly on this part of a practical work; they seem to have made a merit of not adding to this department, by attending too strictly to an observation of his, saying that there may be many more fanciful ways of folding a sheet of paper. So there may, with which it may not be necessary to encumber a book; but why reject those that are useful and of frequent occurrence? why omit giving the mode of imposing fragments that continually occur at the end of a work? and that generally cause loss of time in arranging them, which might easily have been avoided; which omission I have endeavoured to supply: for this is the part of a work on printing that may be equally useful as a reference to the experienced workman as to the novice, and which I have frequently seen much wanted.

Smith’s words are, after enumerating the different Tables of Imposition which he has given—“More Irregular Sizes we have not thought fit to introduce; else we might have drawn out Schemes for Imposing Six’s, 10’s, 14’s, 20’s, 28’s, 30’s, 40’s, 42’s, 50’s, 56’s, 60’s, 80’s, 100’s, and 112’s; these, and several more being Sizes that have been found out not so much for use as out of fancy, to show the possibility of folding a piece of paper into so many various forms.”—p. 257. Upon this passage have all subsequent writers formed their excuse for leaving the different methods of imposing pages in an imperfect and erroneous state: the errors commenced with Luckombe.

As it may facilitate reference, I have given in the following enumeration the initials of the different authors in whose works the same forms will be found.—M. refers to Moxon; Sm. to Smith; L. to Luckombe; St. to Stower; J. to Johnson; H. to Hansard; Ma. to Magrath; and Mas. to Mason. Where there are no initials, the arrangement has not, to my knowledge, been given before in any English book, and is only to be found in this work.

TABLES OF IMPOSITION.

When imposing the first sheet of a new work, it may be serviceable to refer to the preceding observations, for a choice of the best method; and also for directions how to transpose the pages in working the reiteration, when a transposition is required.

The running Number corresponds with that in the Enumeration.

1. ABSTRACT OF TITLE DEEDS.

Enumeration of the TABLES OF IMPOSITION in the preceding pages, with Observations, and reference to the page in which each will be found.

1. Abstract of Title Deeds. J.—H.

Page 335

Abstracts of Title Deeds of Estates are in single leaves, and all the margin is on the left side of the paper; they are usually imposed two pages together, to save expense in press-work. They are stitched together at the corner.

2. Sheet of Folio. M.—Sm.—L.—St.—J.—H.—Mas.

335

3. Sheet of Folio. Hebrew

335

4. Two sheets of Folio, Quired. Sm.—L.—St.—J.—H.

335

5. Three sheets of Folio, Quired

336

Imposing in Quires was formerly much used, when books were more commonly printed in folio than they now are. It may be carried to any extent, by taking care that the folios of the two pages in each form of the first Signature make one more than the whole number quired: thus, if the quire consists of 24 pages, the Imposition of each form will be consecutively 1 and 24—23 and 2—3 and 22—21 and 4—5 and 20—19 and 6—7 and 18—17 and 8—9 and 16—15 and 10—11 and 14—13 and 12; and so for the succeeding forms, taking this order of the pages.

6. Half a Sheet of Folio. M.

336

7. Sheet of Quarto M.—Sm.—L.—St.—J.—H.—Mas.

336

8. Sheet of Quarto. Hebrew

336

9. Two Half Sheets of Quarto, worked together. Sm.—L.—St.—J.—H.

337

10. Half Sheet of Quarto. M.—Sm.—St.—J.—H.

337

Half Sheet of Broad Quarto. Sm.—J.—As the pages are laid down as in No. 10, I have not repeated the arrangement.

11. Half Sheet of Quarto. Hebrew

337

12. Two Sheets of Quarto, Quired

337

This Imposition may be useful where a pamphlet makes but two Sheets.

13. Sheet of Broad Quarto. Sm.—L.—St.—J.—H.

338

14. Sheet of Octavo. M.—Sm.—L.—St.—J.—H.—Mas.

338

15. Sheet of Octavo. Hebrew. Sm.—St.—J.—H.

338

16. Sheet of Broad Octavo. Sm.—L.—St.—J.—H.

338

17. Half Sheet of Octavo. M.—Sm.—L.—St.—J.—H.

339

18. Half Sheet of Octavo. Hebrew.

339

19. Two Half Sheets of Octavo, worked together. Sm.—L.—St.—J.—H.—Mas.

339

I prefer this method of imposing two half sheets of Octavo, which cut up in the regular fold of the paper, to having the signatures in slips on each side of the long cross.

20. Sheet of Octavo with two Signatures, 12 pages and 4. St.—J.—H.—Mas.

339

The four pages are here imposed to cut out of the middle of the Sheet: being in the order of the 7th, 8th, 9th, and 10th. They might also be imposed as the 1st, 2d, 15th, and 16th; both these methods are convenient to the bookbinder.

21. Two Quarter Sheets of Octavo, worked together. Sm.—L.—St.—J.—H.—Mas

339

22. Two Quarter Sheets of Octavo. Hebrew. Worked together

339

 23. Sheet of Twelves, No. 1. M.—Sm.—L.—St.—J.—H.—Mas.

340

The pages of this sheet are arranged in the customary manner, the first page of the offcut being in the outer form.

24. Sheet of Twelves, No. 2.

340

By imposing a sheet of twelves in this manner, the first signature of the offcut being in the inner form, it rises more conveniently for the bookbinder when folding; as it saves him the trouble of turning the offcut over every sheet, and it is no inconvenience to the printer.

25. Sheet of Twelves, to fold without cutting. L.—St.—J.—H.

340

26. Sheet of Twelves. Hebrew

341

27. Two Half Sheets of Twelves, worked together, No. 1. H.

341

The signatures of these two half sheets when quired, will rise regularly when collated, so as to be easily perceived both by the warehouseman and the bookbinder, and be less liable to be overlooked than the following. I give the preference to this arrangement.

28. Two Half Sheets of Twelves, worked together, No. 2. Sm.—St.—J.—H.—Mas.

341

I give this arrangement of the pages of two half sheets of Twelves to be worked together, because it is generally adopted; but the second signature is hid in the sheet, and may easily be overlooked, so as to cause a mistake, both by the warehouseman and the bookbinder. I prefer the preceding arrangement.

29. Half Sheet of Twelves. M.—Sm.—L.—St.—J.—H.

342

30. Half Sheet of Twelves, to fold without cutting. L.—St.—J.—H.

342

31. Half Sheet of Twelves. Hebrew

342

32. Sheet of Twelves, with two Signatures. 20 pages and 4

342

33. Sheet of Twelves, with two Signatures. 16 pages and 8. Sm.—St.—J.—H.—Mas.

343

34. Sheet of Twelves, with three Signatures. 12, 8, and 4 pages

343

35. Sheet of Twelves, with three Signatures. Thrice 8 pages

343

The offcut forms one of the portions of eight pages; the other two are imposed as two half sheets of octavo.

36. Half Sheet of Twelves, with two Signatures. 8 pages and 4. Sm.—St.—J.—H.—Mas.

344

37. Eight pages of Twelves. St.—J.—H.—Mas.

344

38. Sheet of Long Twelves. Music way, No. 1

344

This sheet cuts into three portions of eight pages each, which are inserted into each other.

39. Sheet of Long Twelves. Music way, No. 2

345

There is an offcut of eight pages in this sheet, which forms the inset.

40. Sheet of Long Twelves. Music way. With two Signatures. 16 pages and 8. S.

345

Stower terms this ‘A Sheet of Long Twelves,’ although it is a sheet with two signatures, composed of sixteen pages and eight pages.

41. Half Sheet of Long Twelves. Music way

346

This half sheet perfects as an octavo, and the four middle pages cut out and form the inset.

42. Sheet of Long Twelves, No. 1.

346

The first page of the offcut in this and the following sheet is imposed in the inner form, for the reason given in No. 24.

43. Sheet of Long Twelves, No. 2.

347

In this and the preceding sheet the paper of the sixteen pages folds differently; the first fold of No. 1. is in the back, as an octavo; the first fold of No. 2. is in the head as a quarto.

44. Sheet of Long Twelves, with two signatures. 16 pages and 8. No. 1. L.—St.—J.—H.

347

Luckombe and the subsequent writers term this a ‘Sheet of Long Twelves;’ it is in fact two fragments, one of sixteen pages, and one of eight pages.

45. Sheet of Long Twelves, with two Signatures. 16 pages and 8. No. 2

348

The sixteen pages of this sheet and the preceding, fold as No. 43. and No. 42.

46. Half Sheet of Long Twelves

348

47. Sheet of Square Twelves

349

A sheet of square twelves is imposed the same as a sheet of common twelves; but I have inserted it, because the chase is laid over the form differently: the short cross should be the same as for octavos, and the long cross should be for the offcut.

Half sheets and fragments are laid down the same as common twelves.

48. Two Half Sheets of Long Twelves, worked together

349

This sheet is perfected as an octavo, and the four middle pages form the inset.

49. Sheet of Sixteens. Sm.—L.—St.—J.—H.

349

50. Sheet of Sixteens. Hebrew

350

This and the preceding sheet fold without cutting.

51. Two Half Sheets of Sixteens worked together

350

52. Sheet of Sixteens, with two Signatures. 24 pages and 8

350

53. Half Sheet of Sixteens. Sm.—St.—J.—H.

351

54. Half Sheet of Sixteens. Hebrew

351

55. Two Quarter Sheets of Sixteens

351

56. Sheet of Long Sixteens

351

57. Two Half Sheets of Long Sixteens, worked together

352

58. Half Sheet of Long Sixteens

352

59. Two Quarter Sheets of Long Sixteens

352

60. Sheet of Eighteens, with one Signature. Sm.—L.—St.—J.—H.

353

Luckombe calls this ‘A common Sheet of Eighteens.’ I suppose at that time it was the customary way of imposing a sheet of eighteens; in my opinion it is inferior to No. 62. There are four insets in it—3 of four pages each, and 1 of eight pages.

61. Sheet of Eighteens with three Signatures. No. 1. Sm.—St.—H.

353

This imposition cuts into three slips the longest way of the sheet of paper; and the heads of the pages on one of them are the raw edge of the paper, which will cause additional trouble to the pressman and to the bookbinder, without being attended with any advantage:—If the compositor have not made his pages up to a precise length, the pressman will have to unlock the forms and rectify them, to make register; and the bookbinder will have to trim each of them with a pair of scissars. It may be avoided by turning the pages of this slip round, and placing the heads against the heads of the other signature, if a sheet should be imposed according to this arrangement. It is certainly inferior to No. 62.

62. Sheet of Eighteens, with three Signatures, as three Half Sheets of Twelves. J.—Mas. No. 2

354

This is now the usual method of imposing a sheet of eighteens; it cuts up equal to three half sheets of twelves, and is the most convenient mode both to the pressman and bookbinder, as it is in the regular way of their business.

63. Sheet of Eighteens, with three Signatures. Hebrew

354

64. Sheet of Eighteens, to fold without cutting. L.—St.—J.—H.

355

Luckombe has reversed every page of this sheet in his work, so that the first page would be at the last end of the sheet, the same as Hebrew. Smith has a sheet of eighteens under this title, but it has three Signatures in it.

65. Sheet of Eighteens, with two Signatures. 24 pages and 12. No. 1. Sm.—St.—J.—H.

355

66. Sheet of Eighteens, with two Signatures. 24 pages and 12, as a Sheet of Twelves and Half Sheet of Twelves. No. 2

356

These two last sheets will only be useful when a volume of eighteens is worked in sheets with one Signature in each, which is not often done; I should give the preference to No. 2.

67. Half Sheet of Eighteens. Sm.—St.—J.—H.—Mas.

356

When the white paper is worked off, transpose the four pages 11, 8 and 7, 12—put 11 and 8 in the place of 7 and 12; and 7 and 12 in the place of 11 and 8.

68. Half Sheet of Eighteens. Hebrew

356

When the white paper is worked off, transpose the four pages, 8, 11 and 12, 7, in the same manner as was directed in No. 67.

69. Half Sheet of Eighteens, without transposing the pages. St.—J.—H.

357

Mr. Stower, in his Printer’s Grammar, says, “We have also given a plan for imposing a half sheet of eighteens, without transposing the pages.”

I acknowledge that much time will be saved in the warehouse work, and that it will be more convenient for the printer to do it in this manner; but the saving of trouble, and the convenience of doing work in a particular way, are not always to be attended to. How will the sheet look when cut up?—There will be three signatures; the first will have twelve pages, the same as half a sheet of twelves; the second will consist of two single leaves; and the third of one leaf, thus having three separate leaves in a half sheet; that is, six single leaves in a sheet, which are charged in binding the same as plates. A collection of plays published separately in eighteens, which is not uncommon, will when completed contain many half sheets, and, if printed in this manner, will be a considerable additional expense in binding a number of complete sets. This will cause dissatisfaction in the master printer’s employers, as it is a principle that ought always to be acted on, not to increase the expenditure, when it can be avoided.

70. Sixteen pages of Eighteens. Sm.—St.—J.—H.

357

When the white paper is worked off, transpose the four pages, 7, 10 and 9, 8; put 7 and 10 in the place of 9 and 8; and 9 and 8 in the place of 7 and 10.

In working sixteen pages, or eight pages, of eighteens, there will be two blank pages in each half of the sheet, except it be filled up with advertisements, catalogue, or other matter.

71. Half a Sheet of Eighteens, with two Signatures. 16 pages and 2

357

When the white paper is worked off, transpose the four pages, 7, 10 and 9, 8, as in No. 70.

72. Half Sheet of Eighteens, with two Signatures. 14 pages and 4

357

After the white paper is printed off, transpose the four pages, 37, 40 and 39, 38, as directed in No. 70.

73. Half Sheet of Eighteens, with two Signatures. 12 pages and 6

358

When the white paper is worked off, transpose the four pages, 13, 18 and 17, 14, as directed in No. 70.

74. Half Sheet of Eighteens, with two Signatures. 10 pages and 8

358

When the white paper is worked off, transpose the four pages, 73, 80 and 79, 74, as directed in No. 70.

75. Half Sheet of Eighteens, with two Signatures. 8 pages and 8

358

When the white paper is worked off, transpose the four pages, 37, 44 and 43, 38, as directed in No. 70.

76. Half Sheet of Eighteens, with three Signatures. 10 pages, 4, and 4

358

When the white paper is worked off, transpose the four pages, 73, 76 and 75, 74, as directed in No. 70.

77. Half Sheet of Eighteens, with three Signatures. 8 pages, 8, and 2

359

When the white paper is worked off, transpose the four pages, 37, 44 and 43, 38, as directed in No. 70.

78. Half Sheet of Eighteens, with four Signatures. Four times 4 pages

359

After the white paper is worked off, transpose the four pages, 85, 88 and 87, 86, as directed in No. 70.

In printing collections of plays in eighteens, where each play has separate folios, fragments in every variety arise. When one of four pages occurs, it will perhaps be adviseable, if the number be large, and the presswork not in a forward state, to make a full form of them, by setting the matter up five times: when the white paper is worked off, transpose the four pages, as directed in No. 70.; also take out the first and fourth pages of one of the portions of four pages which occupy the place of the two blanks in No. 78, and put the third and the second in their place.

79. Sheet of Twenties. No. 1. L.—St.—J.—H.

359

I do not approve of this arrangement; for the sheet cuts into five slips, four of which are insets—otherwise they must have five different signatures.

80. Sheet of Twenties. No. 2

360

After the offcut is separated, the first and second folds of the remainder are the same as a duodecimo.

81. Sheet of Twenties. No. 3

360

After the offcut is separated, the first and second folds of the remainder are the same as a Quarto. I have placed the first signature of the offcut in the inner form, for the reason assigned in No. 23.

This and the preceding arrangement are preferable to No. 1, as there is only one offcut in each, which is inserted in the middle when folded; the other pages are imposed as a sheet of sixteens.

82. Sheet of Twenties, with two Signatures. 32 pages and 8

361

83. Sheet of Twenties, with two Signatures. 24 pages and 16

361

84. Two Half Sheets of Twenties, worked together

362

85. Half a Sheet of Twenties

362

86. Half a Sheet of Twenties, with two Signatures. 16 pages and 4 J.

362

87. Half a Sheet of Twenties, with two Signatures. 12 pages and 8

363

88. Two Half Sheets of Twenty-fours, worked together

363

What Stower calls Twenty-fours are longer and narrower than what he calls Long Twenty-fours: I have reversed the terms, and called his Twenty-fours, Long Twenty-fours, and vice versâ.

89. Half a Sheet of Twenty-fours. No. 1

364

90. Half a Sheet of Twenty-fours. No. 2. Sm.—St.—J.—H.

364

These four writers term this arrangement of the pages, ‘the Sixteen-way.’

The difference between No. 1. and No. 2. is, that, when the inset is taken off, the first fold of No. 1. is in the head; and that of No. 2. is in the back, as a sheet of octavo.

91. Half a Sheet of Twenty-fours, to fold without cutting. L.—S.

365

92. Half a Sheet of Twenty-fours, with two Signatures. 20 pages and 4

365

93. Half a Sheet of Twenty-fours, with two Signatures. 16 pages and 8. L.—St.—J.—H.

366

94. Half a Sheet of Twenty-fours, with three Signatures. 8 pages each

366

95. Quarter of a Sheet of Twenty-fours. H.

366

When the white paper is worked off, transpose the four middle pages; put 5 in the place of 7,—6 in the place of 8,—7 in the place of 5,—and 8 in the place of 6.

96. Two Half Sheets of Twenty-fours, worked together. Hebrew

367

97. Half a Sheet of Twenty-fours. Hebrew. No. 1

368

98. Half a Sheet of Twenty-fours. Hebrew. No. 2

368

99. Two Half Sheets of Long Twenty-fours, worked together. Sm.—L.—St.—J.—H.

369

Luckombe has transposed the pages of this table in his work. I have put the first page of the second signature in the inner form, which causes it to rise better in collating and folding: Stower has it in the outer.

100. Half a Sheet of Long Twenty-fours. No. 1

369

101. Half a Sheet of Long Twenty-fours. No. 2. L.—St.—J.—H.

370

102. Half a Sheet of Long Twenty-fours, to fold without cutting. L.—St.—J.—H.

370

103. Half a Sheet of Long Twenty-fours, with two Signatures. 20 pages and 4

370

104. Half a Sheet of Long Twenty-fours, with two Signatures. 16 pages and 8. Sm.—L.—St.—J.—H.

371

Luckombe has placed the foot of each page where the head should be, in the range commencing with page 1.

105. Two Half Sheets of Long Twenty-fours, worked together. Hebrew

371

106. Half a Sheet of Long Twenty-fours. Hebrew. No. 1

372

107. Half a Sheet of Long Twenty-fours. Hebrew. No. 2

372

108. Half a Sheet of Long Twenty-fours, with two Signatures. 20 pages and 4. Hebrew

372

109. Half a Sheet of Long Twenty-fours, with two Signatures. 16 pages and 8. Hebrew

373

110. Two Half Sheets of Square Twenty-fours, worked together

373

111. Half a Sheet of Square Twenty-fours. L.—St.—J.

374

112. Sheet of Thirty-twos. No. 1

374

113. Sheet of Thirty-twos. No. 2. L.—St.—J.—H.

375

In my opinion No. 1. is a more preferable method of imposing a sheet of 32mo. than No. 2.; as the sheet in the first instance folds into the regular folio, then into quarto, octavo, square sixteens, and thirty-twos; whereas No. 2. folds into long folio, quarto, long octavo, &c.

Both of them would be inconvenient, except for children’s books, tracts, and other temporary articles; as sixty-four pages in one signature would be too many to fold neatly for book work, for such purpose I should prefer four signatures in the sheet, each of which would be equal to a sheet of octavo.

114. Two Half Sheets of Thirty-twos, worked together

376

115. Sheet of Thirty-twos, with two Signatures. 48 pages and 16

377

The sheet in the first instance cuts up in the regular fold; the half sheet with signature B in it, folds into quarto, octavo, square sixteens, and thirty-twos; the other half sheet cuts up lengthways into two equal parts, containing sixteen pages each, one of which is an inset for signature B, the other forms signature C.

116. Sheet of Thirty-twos, with two Signatures. 40 pages and 24

378

The sheet cuts up in the regular fold, and the half sheet folds as No. 115.; the other half sheet cuts in two lengthways, one of which contains sixteen pages of signature C; the other sixteen pages cut in two, eight pages of which are an inset for signature B, the other eight are an inset for signature C.

117. Sheet of Thirty-twos, with four Signatures. 16 pages in each. Sm.—St.—J.—H.

379

I have arranged the signatures of this sheet differently from the preceding writers. They have the two first signatures on different half sheets: I have placed them on the same half sheet, and the third and fourth signatures on the other half sheet, so as to cause them to rise in a regular way.

This sheet is equal to four sheets of octavo; two of which are imposed on each side of the long crosses in a pair of chases: eight pages of the first signature, the same as the outer form of a sheet of octavo, are laid down in the left hand quarter of a chase, the other eight pages, similar to the inner form of a sheet of octavo, are laid down in the right hand quarter of the other chase; the fourth signature is imposed in the two other quarters, which will lie together as the chases are upon the imposing stone; the second and third signatures are imposed in a similar manner on the other sides of the long crosses.

118. Half a sheet of Thirty-twos. L.—St.—J.—H.

380

119. Half a Sheet of Thirty-twos, with two Signatures. 24 pages and 8

380

120. Half a Sheet of Thirty-twos, with two Signatures. 20 pages and 12

380

121. Half a Sheet of Thirty-twos, with four Signatures. 16 pages, 8 pages, 4 pages, and 4 pages. J.—H.

381

122. Two Quarter Sheets of Thirty-twos, worked together. Sm.—L.—St.—J.—H.

381

123. Sheet of Thirty-sixes, with three Signatures

382

This sheet perfects the same as a twelves. It cuts into three equal parts across the sheet, each portion of which contains all the pages in the signature.

124. Sheet of Thirty-sixes, with six Signatures

383

This sheet cuts up into portions of eight pages and four pages each, the four pages forming an inset; so as to make each signature equal to a half sheet of twelves.

125. Sheet of Thirty-sixes, with two Signatures. 60 pages and 12

384

126. Two Half Sheets of Thirty-sixes, worked together

385

127. Half a Sheet of Thirty-sixes. L.—St.—J.—H.

386

128. Half a sheet of Thirty-sixes, to fold without cutting. L.—St.—J.—H.

386

129. Half a Sheet of Thirty-sixes, with three Signatures

387

This form perfects as an octavo. It folds as three half sheets of twelves.

130. Half a Sheet of Thirty-sixes, with two Signatures. 24 pages and 12. Sm.—St.—J.—H.

387

This form perfects as an octavo. The three last writers, in their works on printing, have made the middle twelve pages perfect foot to foot, so that they will be cut out at the head, and fold at the foot; I have reversed them, to cause them to be cut out at the foot, and fold at the head.

131. Two Quarter Sheets of Thirty-sixes, worked together

388

When the white paper is worked off, transpose the four pages, 11, 8, and 7, 12, in signature B, and 29, 26, and 25, 30, in signature C, in the manner directed in No. 67. (half sheet of eighteens), for each of these quarter sheets is similar in arrangement to that form.

132. Half a Sheet of Forties. No. 1. L.—St.—J.—H.

388

The sheet cuts up into five slips of one page in depth, four of which are insets; it appears to me an inconvenient method, which I have endeavoured to improve in the next article. It perfects as an octavo.

133. Half a Sheet of Forties. No. 2

389

In this arrangement the paper folds in the regular way, first into folio, then into quarto, octavo, sixteens, and thirty-twos, with one inset of eight pages. In my opinion it is preferable to the preceding method. It perfects as an octavo.

134. Half a Sheet of Forties, with two Signatures. 32 pages and 8

389

The arrangement of the 32 pages is the same as for half a sheet of thirty-twos, in No. 118. The 8 pages of signature C form the offcut.

135. Half a Sheet of Forties, with two Signatures. 24 pages and 16

390

136. Half a sheet of Forties, with three Signatures. 16 pages, 16 pages, and 8

390

137. Two Quarter Sheets of Forties, worked together

391

138. Half a Sheet of Forty-eights, with three Signatures. Sm.—St.—J.—H.

391

These writers have placed the first signatures on the different half sheets; I have placed them on the same half sheet. It is similar in the arrangement of the pages to three sheets of octavo, and perfects the same as a form of twelves.

139. Quarter of a Sheet of Forty-eights. L.—St.—J.—H.

392

The same arrangement of the pages as a sheet of twelves, and perfects as such.

140. Quarter of a Sheet of Forty-eights, to fold without cutting. L.—St.—J.—H.

392

It is the same as a sheet of twelves without cutting.

141. Two Quarter Sheets of Forty-eights, worked together. No. 1

392

These are equal to two sheets of twelves, and are arranged on each side of the short cross, and perfect as a twelves.

142. Two Quarter Sheets of Forty-eights, worked together. No. 2. L.—St.—J.—H.

393

These two quarter sheets are arranged on each side of the long cross, and perfect as an octavo.

143. Quarter of a Sheet of Forty-eights, with two Signatures. 16 pages and 8. L.—St.—J.—H.

393

Stower imposes this form in three slips, and makes one of them an inset; and the slip with the first signature, has the heads of the pages to the raw edge of the paper: I have arranged the 16 pages as a sheet of octavo, and the 8 pages of signature C form the offcut.

144. Half a Sheet of Sixty-fours

394

However much I disapprove of the arrangement of the pages in many of the Tables of Imposition in Luckombe’s and Stower’s works, on account of the uncustomary and inconvenient manner of the paper folding, yet I have given all that are in their books thus far, for the reason I stated in page 328; but when we come to sixty-fours, a size that is seldom printed, I think it is unnecessary to give more than one mode, and I omit the one that has been usually given, and insert in its place what I conceive to be an improvement. The old plan folded into folio, long quarto, octavo, long sixteens, &c.; the plan here inserted folds into folio, quarto, octavo, sixteens, &c. in the customary way. If any printer choose to adopt the other plan, he will find it in Luckombe, Stower, Johnson, and Hansard.

145. Two Quarter Sheets of Sixty-fours, worked together

394

146. Quarter of a Sheet of Sixty-fours. L.—St.—J.—H.

395

The pages of this form are laid down in the same order as half a sheet of thirty-twos, No. 118.

147. Quarter of a Sheet of Sixty-fours, with two Signatures. 16 pages in each. L.—St.—J.—H.

395

The pages of this form are laid down in the same order as two quarter sheets of thirty-twos, worked together, No. 122.

148. Quarter of a Sheet of Sixty-fours, with two Signatures. 24 pages and 8

395

The pages of this form are laid down in the same order as half a sheet of thirty-twos, with two signatures. 24 pages and 8, No. 119.

149. Half a Sheet of Seventy-twos, with three Signatures. Sm.—L.—St.—J.—H.

396

I have varied from the old plan of imposing half a sheet of seventy-twos, nor did I think it of consequence to crowd the book unnecessarily with giving what I consider inferior modes of imposing in sizes that rarely occur. This form has been usually given to cut up into three slips the longest way of the paper; I have given it in the manner, that when perfected, it will cut up into six portions, with the pages of each the same as a sheet of twelves. It perfects as a twelves.

150. Half a Sheet of Seventy-twos, with six Signatures

397

This sheet when perfected cuts up into twelve portions, each of which is similar in the arrangement of the pages to half a sheet of twelves.

The fragments of No. 149. will be imposed in the same order as those of a sheet of twelves; and those of 150, in the same order as those of half a sheet of twelves.

151. Half a Sheet of Ninety-sixes, with four Signatures

398

When perfected it cuts up into eight portions, each of which is similar to a sheet of twelves. It perfects as a twelves.

152. Half a Sheet of Ninety-sixes, with six Signatures. Sm.—L.—St.—J.—H.

399

I have placed the first signatures on the same half sheet; the preceding writers scattered them on both. It is laid down as six sheets of octavo, and perfects as an octavo.

153. Half a Sheet of One Hundred and Twenty-eights. Sm.—L.—St.—J.—H.

400

It is laid down as eight sheets of octavo, and perfects as an octavo.

Layout for Title Deeds

William Savage, A Dictionary of the Art of Printing, 1841


imposition

The plan of arrangement of the pages of type in a chase so that they will read consecutively when the printed sheet is folded. It is a term which means literally "in position," and originated in letterpress printing.

There are four standard methods of imposition: 1) sheetwise; 2) work-and-turn; 3) work-and-tumble; and 4) work-and-twist. The purpose of having different schemes is to obtain maximum economy in printing.

Sheetwise imposition, also known as "work-and-back," "front-and-back," or "print-and-back," requires two image carriers per color, one each for the front and back of the sheet. This method is used for printing jobs where the number of pages to be printed on each side of the sheet is large enough to utilize the full capacity of the press.

Work-and-turn imposition, also known as "print-and-turn," is used where it is practical to print both sides of the sheet from a single image carrier per color. It is frequently used, and requires relatively large presses because the sheet will carry two complete units, each occupying one-half of the sheet. The sheet is either slit during backup or is cut apart after printing. Workand-turn imposition cuts the number of sheets to be printed by 50%, but it generally requires larger and more expensive presses than sheetwise imposition.

Work-and-tumble imposition, also known as "print-and-tumble," "workand-roll," or "work-and-flop," is used less frequently than either of the two previous methods. It is selected when a work-and-turn form cannot be used, or when two sheetwise forms would have to be run on a sheet of difficult dimensions. This method needs only one image carrier for printing both sides of the sheet, and in this respect it is similar to work-and-turn.

Work-and-twist imposition, also known as "work-and-twirl," differs fundamentally from all three previous schemes. While the first three are methods designed to produce sheets printed on both sides, work-and-twist imposition solves problems pertaining to one-side printing, e.g., printing blank rule and tabular forms, with cross rules in one section and vertical rules in the other. In this method, two separate sections, or divisions, of an individual form are imposed and locked up together in such a manner that they may be printed side by side on a double-sized sheet in one impression. After completion of the run, the already printed paper is repositioned face up for the second printing from the same image carrier. Work-and-twist imposition is actually rarely used, as it requires nearly perfectly square stock for execution.

Melcher, Daniel, and Nancy Larrick. Printing and promotion handbook …3rd ed. New York. McGraw-Hill. 1966.

Radford, Richard George. Letterpress machine work. New York. Staples Press. 1951. 2 vol.

Reed, John Henry. The science of imposition…Chicago. Inland Printer. 1928.

Stevenson, George A. Graphic arts encyclopedia. New York. McGraw-Hill. 1968.

Strauss, Victor. The printing industry…Washington, D.C. Printing Industries in America. 1967.


impregnated fabrics

Fabrics in which the interstices between the yarns are completely filled with the impregnating compound throughout the thickness of the material, as distinguished from sized or coated fabrics, where the interstices are not completely filled. Sometimes the reverse side of impregnated fabrics are sized to insure the adhesive sticking to the cloth. When a grain or pattern is applied to impregnated fabrics, it is worked directly into the cloth, rather than on a surface coating as is the case of coated fabrics. See also: BOOK CLOTH.

Library Binding Institute. Library binding handbook. Rev. ed. Boston. Library Binding Institute. 1971.

Perry, Kenneth Frederick, and Clarence T. Babb. Instruction units in bookbinding; Pt. 1: fabrikoid and buckram books. Greeley, Colo. Colorado State College of Education. 1935.

U.S. National Bureau of Standards. Fabrics for book covers. Washington, D.C. U.S. Government Printing Office. (Product Standard PS 9-68). 1968.


impregnated paper

A paper in which a material such as latex or plastic is made to permeate the paper rather than merely coat it, thus adding to the wet strength, tearing resistance, and oil or grease resistance of the paper. The untreated paper used in its manufacture is known as saturating paper.

Cunha, George Daniel Martin. Conservation of library materials. Metuchen, N.J. Scarecrow. 1967.

Gazurian, Johnny A. The advertising & graphic arts glossary. Los Angeles. Los Angeles Trade-Technical College. 1966.


impressed watermark

See: WATERMARK.


impression

1. The pressure required to transfer ink from one surface to another, as, for example, plate to paper, or plate to blanket, etc. It is usually expressed in terms of thousandths of an inch beyond that needed to produce first contact between two printing cylinders. 2. A printed copy or the result of impressing ink upon a receiving surface. 3. The indentations remaining in paper as a result of the pressure used in letterpress printing plus the dampness of the paper. These impressions were often quite pronounced in early letterpress printing. See also: CONVEX COVERS. 4. The effect produced by stamping, blocking, printing, or tooling a design or lettering on the covers of a book. 5. All copies of a work printed at one time from one setting of type. There may be several impressions (presumably unaltered) of one edition, each new printing from standing type or original plates constituting a new "impression" of the work. If, however, the pages are reimposed to produce a different format, the resultant impression is a different edition. 6. A single copy of a print or map. 7. A print taken by means of a special engraving press, from an enlarged plate.

American Library Association. Editorial Committee. Subcommittee on library terminology. A. L. A. glossary of library terms, with a selection of terms in related fields. Compiled by Elizabeth H. Thompson. Chicago. American Library Association. 1943.


IMPRESSION SHEET

A sheet of stout even paper, that fits exactly, without any play, the inside of the outer tympan: this sheet is used in fine work to place the overlays upon next to the parchment, and when a sheet of any work is thus made ready at a press, the succeeding sheets of the same work, at the same press, are made ready much more expeditiously, than if all the overlays have to be placed for each sheet on the tympan sheet.—See Making ready.