Learn to Draw > Enlarging and reducing imagesThis review of drawing techniques does not exhaust the possibilities, and much can also be done with combinations of different techniques. Some materials do not go well together, such as pencil and chalk, nor is it possible to use a wash over charcoal. It is better, however, to experiment with the chance of finding interesting new combinations than to be too strictly conflned by cramping rules as to what is "correct" or "allowed."
Drawing technique includes a knowledge of the purely mechanical processes of enlarging and reducing. Every draftsman and painter must at some time or other alter the size of a sketch or drawing to fit another format. The simplest method, which can be used even by quite an inexperienced draftsman, employs a network of squares.
The original drawing is conveniently squared up into a grid pattern, and correspondingly larger or smaller squares are laid over the paper onto which it is to be reproduced for the enlargement or reduction. It is comparatively simple to copy the lines in each square of the original onto the corresponding squares of the reproduction.
It is best to draw the new squares onto tracing paper, for once the new drawing is done, they are not wanted. The back of the tracing paper should be colored and the new drawing traced onto its paper. The flat side of a pastel is the best thing for this, for then the tracing can be uniformly wiped out. Carbon paper is not good because the "carbon," being generally an aniline dye, is indelible. Paper which has been rubbed over with chalk is suitable.
The pantograph is hardly ever used in freehand drawing, but a new copying instrument called a Bell Optican (antiscope) is very useful. It works on the principle of the epidiascope, but with greater precision. It reflects a well-illuminated image or drawing and projects it through an enlarging lens onto a surface placed at right angles to the original. Usually it does not enlarge anything above about six inches square, and cannot make" above a six-fold linear enlargement.
If the original is larger than six inches square, the enlarging has to be done piecemeal, which requires some practice and skill; and if an enlargement greater than six fold is wanted, the process has to be repeated in stages. This is liable to produce error, so that squaring up is really more satisfactory. The Bell Optican can also be used with a lens that reduces the size of the original, but its scope is rather limited.
This machine should, of course, not be used for copying other people's drawings, which would be pure theft. Nor is it much less objectionable to use photographs as models for a drawing which could never be made freehand. Its use is quite justifled however to bring up one's own small sketch to the required size or to enlarge a part of it to make a picture. Work can be continued on the enlargement, improving and adding, and being all one's own work there is no moral objection to it.
Etchers, engravers, and miniaturists have used the reducing glass ever since it was invented; no one accuses them of dishonesty or lack of artistry for doing so. Art is not a game which must be played according to rules to make it more difficult. The purpose of technique is to remove material hindrances from the free expression of the spirit.
Anyone who does much drawing in a professional way and makes use of ruler and set square should consider investing in a "drafting machine." It consists of a set square held in equilibrium by weights or springs, which can be moved all over the board without altering its angle. It is flrmly mounted on a board and made in many sizes, from simple flat boards that lie on the table to the largest drawing boards which move by balancing weights or even hydraulic pressure. This elegant apparatus is intended for architects and technical draftsmen, but it makes work a pleasure for artists working on a large scale who use rule and square for guiding lines and need exact measurements, even though they work in freehand.