Practice drawing with the use of a grid...

Grid superimposed on top of a sketch of horse and cat.

ENLARGING AND REDUCING PICTURES.

       A simple picture may be enlarged by means of clots and dotted lines to guide the eye, as shown on the next page, where we have a number of compound curves applied to vase forms, which are to be reproduced the same size below and enlarged on the opposite page. If, however, the picture is not a single figure, but contains a large amount of detail, it is best to enlarge it by means of squares, as shown just left. To do this, take the original, and divide it into a number of squares, as shown in the small figure. If the picture is desired twice as long as the original make a square twice its dimensions, or, if it is to be reduced and it is desired to have it only half the length of the copy, then the square should be made only one-half the dimensions of the original. For instance, Fig. above, left is a small picture, which measures two and one-half inches long by two inches wide. We want a picture five inches long, consequently, we draw a square twice the dimensions of the small picture, or five inches long by four inches wide. This large square is now divided into five squares in length by four squares in width, or just the same number as have been made on the copy, but, of course, those are proportionately smaller.
       The eye and hand now have a guide, and by noting the relative position of the outlines in the original to the corners and edges of the squares, and by carefully following this guide an enlarged picture, correctly proportioned, may be made.
       In placing the details of the picture care should be taken to place correctly in the enlarged picture according to their position in the copy. If the eye of the horse is in the corner of a square in the small picture, a correspondingly large one should be similarly placed in the enlarged picture. The cat's tail extends to the upper line of the third row of squares in the original, and should do the same in the reproduction. In drawing the horse's ears, note the proportion of the small square that is covered by them, and by following the same proportions in the large square, they may be accurately enlarged.
       To reduce a picture, make a square the size desired; divide it into squares, and the copy into the same number of squares. This will furnish a guide by which any large picture may be accurately reduced to the size desired, the same as in enlarging. Practice on the pictures given, on loose paper, and do not attempt to reproduce on the pages left in this book until creditable work can be done. Cline

Above you can see the sample grid drawings that I've made from pictures cut and laminated from magazines.
Students may use these to practice enlarging and reducing images on grids during free drawing time in the art classroom.