Quadrats

Pieces of type metal of the depth of the body of the respective sizes to which they are cast, but lower than types, so as to leave a blank space on the paper when printed where they are placed.

An en quadrat is half as thick as its depth; an em quadrat is equal in thickness and depth, and being square on its surface, is the true quadrat (from quadratus, squared); a two em quadrat is twice the thickness of its depth; a three em three times, a four em four times, as their names specify. Four ems are the largest quadrats that are cast. They are used to fill out short lines to form white lines, and to justify letters, figures, &c., in any part of the line or page. Four-em quadrats are rarely cast larger than Pica. English and Great Primer do not exceed three ems, nor does Double Pica exceed two ems.

In casting em and en quadrats the utmost exactness is necessary; they also require particular care in dressing, as the most trifling variation will instantly be discovered when they are ranged in figure work; and unless true in their justification, the arrangement will be so irregular, that all the pains and ingenuity of a compositor cannot rectify it. The first line of a paragraph is usually indented an em quadrat, but some printers prefer using an em and en, two, or even three ems for wide measures. An em quadrat is the proper space after a full point when it terminates a sentence in a paragraph. En quadrats are generally used after a semicolon, colon, &c., and sometimes after overhanging letters.

Circular or curved quadrats are made of various sizes so as to form circles from one to twenty-four inches in diameter; each piece is exactly one eighth of a full circle, and when combined with similar pieces, will form quarter, half, three-quarter, and full circles. By reversing the combination of some of the pieces, serpentine and eccentric curves may be made of any length or depth. These curvilinear quadrats are of two kinds— inner quadrats with convex surface, and outer quadrats with concave surface. The curved line is produced by placing the convex and concave surfaces parallel to each other, so that when locked up firmly they hold the type inserted between them. The other sides of the quadrats are flat and right-angled, to allow a close introduction of type, and an easy justification with ordinary type.

Select two outer quadrats (each marked with the same number), join the smaller ends and justify the extremities carefully with ordinary quadrats, set the line of type in the hollow of the curve, but without justification, then insert two inner quadrats (of the same number) of smaller size than the outer quadrats—the size of the inner quadrats will depend upon the size of the type. A line, a canon for instance, will require smaller inner quadrats than will be needed for a line of Pica, and vice versâ. As!the one increases the other diminishes. An ordinary clock dial will afford a good illustration. The space between the numeral X and I is one fourth of a circle. The curved line described around the foot of these numerals is much less than the curve at the top; if the size of the numerals from X to I is decreased, the inner curve will be greater; if it is increased, it will be less. This will explain why the inner quadrat should be of less size than the outer, and why it should diminish as the size of the type increases. The curve of the inner quadrat should be perfectly parallel with the curve of the outer quadrat. When they are parallel they bind the type between firmly in every part.

Then justify the line of type. As the sizes of type vary with different foundries, it will often be found that the inner quadrat of the nearest suitable size will not meet the type in every part. This difficulty may be obviated by introducing slips of the same length as the line of type. This increases the distance between the quadrats until the curved surfaces are perfectly parallel with each other. The line of type cannot be justified, unless they are parallel. When the inner and outer quadrats are thus adapted to each other, they not only bind the type firmly, but will also present a perfect surface on the other side. Unless they are parallel on the inner sides, and flat and square on the outer sides, the justification is not good; and the remedy must be found in changing the size of the inner circle, or in increasing the distance between the curved lines by the use of large type, or by paper or cardboard.

When thus composed the type will be perfectly tight and secure, and the curved white line strictly accurate. As the quadrats are perfect segments of a large circle, they cannot be increased or diminished without destroying the truth of the curve. If the thin ends are pieced out with common quadrats, good justification will be rendered impossible. If they are shortened by cutting of them, they are ruined bits of lead; or short pieces of card between the curved surfaces are also wrong; they destroy that exact parallelism which is necessary for the security of the type.

Very accurate justification of the outer extremities of the quadrats is also indispensable. If the curved surfaces are kept parallel, and the flat surfaces kept square, no difficulty will be found in using them; -and they will prove a valuable aid in ornamental printing.