Printing and bookbinding for schools

by Samuel Jesse Vaughn

IMPOSITION

Imposition is the arranging of the type masses in proper order on the stone, and the fastening of them into the chase.

Fig. 18.—BACK VIEW.

Fig. 18.—FRONT VIEW.

The imposing stone, Fig. 18, is a smooth marble slab on which the forms are placed for locking up ready for the press. The stone may be laid upon a box, bench or table, but both stands and cabinets are made for this purpose. It is properly bedded in its “coffin” by placing putty along the edges of the bed and along any cross supports which may run under the stone. Then when the stone is placed into this receptacle, it remains solid and level and free from strain. It should project a short distance above the frame of the bed in order to render easy the removal of the forms to and from the galley.

Fig. 19.

The chase, Fig. 19, is a steel or cast-iron frame, into which the forms are locked to be put into the press. The size of a press is based upon the inside dimensions of the chase. A 10 × 15 press is one that accommodates a 10 × 15 chase. The skeleton chase is a steel chase with a very narrow frame. This makes the inside considerably larger. A skeleton chase for a 10 × 15 press is practically 11 × 16, making a clear gain of almost an inch each way.

When the type has been proofed, corrected, made up, and tied, the form is slipped from the galley to the stone, and is then ready for the lockup, Fig. 20.

Fig. 20.

A chase is put upon the stone in such a position as to form a frame about the type, which as a rule should occupy the central part of the space enclosed by the frame. A roller supporter, a, Fig. 20, is placed in each end of the chase and pieces of furniture are built out solidly from the type form to one side and one end of the chase.

Fig. 21.

Furniture, Fig. 21, and b, c, Fig. 20, is the name given to pieces of wood and metal, which are used to build around the forms in the process of locking them into the chase. Furniture varies by the em in width and by 5 to 10 ems in length when cut labor saving. Metal furniture is more modern and makes possible more accurate work; but for beginners, it has its disadvantages. The metal is soft and of considerable weight, making heavier forms; and if a piece is dropped upon the stone or even upon the floor, which frequently happens, it probably has a corner or an edge battered. In the lockup, occasionally this small defect may cause the “pi” of the whole form. Reglets are a kind of wood furniture similar in size and use to leads and slugs but are largely used as furniture in locking up forms. In leaded forms which have to be kept for sometime, reglets are substituted for the leads and slugs. They are very much cheaper, and they relieve the necessity for large quantities of the more expensive leads and slugs. Wood furniture, which comes by the case or by number of pieces, is cheap, durable, not easily injured, and on the whole, quite satisfactory for school use. A small amount of metal furniture, which is sold by weight, is desirable in every printshop.

When the furniture has been built in at one side and one end of the form as indicated above, quoins are placed at the other side and the other end about midway between the type and the chase.

Fig. 22.

Quoins, Fig. 22, are devices for locking the forms into the chases. There are two chief kinds, one consisting of two separate wedge shaped pieces of hard metal with notched sides, which by the use of a key are made to slide in opposite directions against each other. The danger of these quoins in the hands of schoolboys is that, not realizing how easily good forms are held, they persist in trying to screw the quoin to the last notch, frequently endangering the chase and ruining the quoins. The other kind is constructed of two pieces of metal joined by springs and opened by the use of a key operating a nut which, after a slight expansion of the quoin, releases its hold and allows the parts to spring back together. This quoin is safe for the form and for the chase, and is itself not battered in the process of locking up.

After the quoins have been put into proper position, pieces of furniture are fitted in on both sides of the quoins.

The pieces of furniture are usually a little longer than the sides of the form against which they fit. They are always placed around the form in such a way that they can not bind against each other so as to prevent the pressure from striking the type squarely, Fig. 20.

With the key, Fig. 22, the quoins are very slightly and uniformly tightened. Then the planer is used.

Fig. 23.

The planer, Fig. 23, is a smooth faced block of hard wood similar to the proof planer, but is usually smaller and not covered with felt. This is laid on the face of the form on the stone and tapped lightly with a mallet, in order to make sure that the faces of all the type are at the same level—no letters projecting so as to be broken or to injure the rollers, or, at best, to ruin the impressions.

After this, the printer tightens the quoins gradually, giving a slight turn to each quoin in succession. There is danger of the beginner’s getting the lockup too tight, causing the form to spring up from the stone and the chase to spring and even to break. If the composition is good and the furniture is properly placed, it does not require a very tight lockup to hold. Before removing the chase from the stone, the lockup should be tested by raising one side of the chase very slightly and tapping the furniture to see if any of the type are loose. If the form holds, it is ready for the press.

Forms for Four and More Pages. When there are a number of pages instead of one to be dealt with, the imposition is considerably more complicated.

Fig. 24.

Any piece of printing of four or more pages has an outside and an inside section. Page one and all the pages that are printed on the same side of the paper with it constitute the outside section. Page two and all the pages that are printed on the same side with it are the inside section. A four page printed sheet is called a sheet folio. The best way to handle such a four page form is by the work-and-turn method, provided the press is large enough to accommodate the four pages at one time. By this method, the pages are arranged as in Fig. 24. Note that in this form as in any other outside form, page one is at the lower left hand corner with the foot of the page toward the printer. Margins are determined by measuring from the front of type pages one and two the width of the page plus twice the desired margin to the backs of pages three and four. Then the length of the page plus twice the margin is measured from the foot of pages one and four to the head of pages two and three.

In this case, the stock is cut double the length of the finished job. When it has been printed on one side, and the ink has dried, it is turned and given the same impression on the other side. Of course, in printing this second side, care must be taken to reverse the paper so that pages two and three back up one and four at one end, and one and four back up two and three at the other end. When the ink of this impression is dry, the sheet is cut at line XX making two complete folios from one sheet.

With school boys working on a small press, the four pages are often handled in two separate forms of two pages each.

Fig. 25.

When so divided, each pair may be imposed in exactly the same order as in the four page form. In this case the paper is cut to exact size and pages one and four are printed on one side. When the ink dries, it is run through the press again and pages two and three are printed on the other side, completing the work.

An eight page form, or a sheet quarto, for a sufficiently large press, may be imposed after the work-and-turn method as in the case of the four page form. The numbered rectangles in Fig. 25 show the arrangement of pages in the work-and-turn method of imposing an eight page form. It will be observed that pages in the outside section of an eight page form are in the same order as those of a four page form. For a press that can accommodate only four pages, the inside and outside sections are imposed exactly in the same order as in Fig. 25, but are used as separate forms.

When we undertake the imposition of an eight page job, we meet the problem of margin for trim, which has not been encountered in the previous forms. In an eight page piece of work, there must be two folds and since the sheets are folded after they are printed and before they are cut, it is evident that some allowance must be made for trimming the fold at the top of the pages. Since in folding, the edges are probably not even, it is necessary to trim them also. Thus it is clear that allowance must be made for trim around each pair of leaves. Fig. 25 represents a half sheet of standard 25 × 38 paper laid on the eight page form imposed by the work-and-turn method. The line XX indicates where the printed half sheet is cut before folding. The dotted lines indicate the margins allowed for trim after folding. The method of measuring for the imposition is as follows: Suppose the type pages to be four by seven inches and centered in the pages, and the margin, after trim, to be one inch all around each page.

It is apparent then that the backs of type pages 8 and 5 are two inches from the backs of pages 1 and 4. The location of pages 7 and 6 is determined by measuring half the length of the half sheet, or 12½ inches in this case, from the front edges of type pages 1 and 4. The distance then from 8 to 7 and from 5 to 6 is 2½ inches or 15 ems pica, making ½ inch for trim. One-half of 19 inches, or the other dimension of the half sheet, measured from the foot of type page 1 to the head of 4, places the distance of 2½ inches between 1 and 4. This allows ½ inch here also for trim.

In this work, some prefer simply to fold the paper and use it for measurement, but in any case when the margins are determined, they are built in with appropriate furniture and the form is locked up. It is well to remember that, viewed from the foot of the pages in a form, odd numbered pages are always at the left of even numbered pages.

In most of the work of this character, the pages are so large that only two may be accommodated by a small press. In this case, the eight pages are imposed in pairs as follows: One and eight, two and seven, three and six, and four and five. It will be observed that the sum of the page numbers of any pair is always one greater than the whole number of pages.