The principle of these three kinds of [O] designing paper is identical, the size preferred being left to the pleasure of the designer. If a design is to be made for a great number of needles, say 600, 900, 1200, etc., it will be best to use the smallest size; whereas in a design for only 100 to 200 needles the larger sizes may be employed.
Practical Use of the Heavy Square in Designing Paper.
The heavy square serves as a unit of measurement, as well as a means of calculation, and shows readily and exactly the size of the design. The eye becomes accustomed to grasping the meaning of this large square, and comprehends at a glance the situation. For instance:
On 8 × 8 paper, 25 squares means 8 × 25, or 200 rectangles each way. 10 × 10 paper, 10 × 25, or 250 rectangles each way. 10 by 12 paper, 10 × 25, or 250 rectangles one way, and 12 × 25, 300 rectangles the other way.
These rectangles in actual work represent threads or ends, thus:
200 ends on 8 × 8 paper require 25 squares. 300 " 10 × 10 " " 30 " 450 " 10 × 12 " " 45 squares one way, and 450 ÷ 12, or 37 squares + 6 lines the other way.
The squares will also assist in putting the weave in a design. For example: Suppose a design for a damask table-cover is required, having for weaves the 8-leaf satin. By using the 8 by 8 paper the “risers” or “sinkers” of the 8-leaf satin are found in the same place in each square, thus any error in forming the weave is at once detected. Sometimes more than one square is required for ascertaining this fact; suppose in the preceding example the [O] paper to be 10 by 10, then the number of threads represented by four successive squares = 4 times 10, or 40, being five repeats of the 8-leaf satin, as 5 times 8 = 40.
Selection of Designing Paper for Single Cloth.
For single cloth the character of the designing paper is ascertained by the number of warp and filling threads required per inch in the finished fabric. For example: A damask fabric with a texture, when finished, of 80/120 (80 ends warp and 120 picks filling per inch) will require a designing paper of corresponding proportion, or as 80 is to 120, = 8 × 12.
In stripes, checks, etc., the texture in part of the fabric is changed; such changes require separate designs. If the difference is only slight, one kind of paper is used. Select the paper derived through the proportion of the two as required. For example: A dressgoods fabric forming two distinct effects in one repeat of 400 warp-threads (200 successive ends required for each effect).