Diagonal Method of Enlarging and Reducing

The Start of the Diagonal Method of Enlarging and Reducing

Only one drawing, about 4 x 6 inches in size, not four drawings, as indicated, are to be made. Proceed thus: draw a rectangle as in A. Intersect with diagonals as shown in A and B.

Intersect the diagonals with a horizontal line as in C and finally with a vertical intersecting line as in D. All lines inside of the rectangle should be made very light. They are merely guide lines to be erased when the drawing is completed.

Blackboard Exercise – Draw the lines in Fig. 6 on the blackboard with the guide lines, and let the pupils copy them by means of the triangular guide lines. The first one by the aid of a single oblique line. The second by the aid of two oblique lines; the third with two oblique lines and one horizontal line; the fourth aided by the addition of a vertical line.

Errors Quickly Noted – For the beginner, even a common vase or teacup is a difficult subject. Straight, upright and oblique guiding-lines are helpful in drawing curved objects. The following diagrams will make the method clear. By this means, as will be observed, the several parts are balanced with ease, and errors quickly noticed and corrected. The use of these lines accustoms the pupil to judge the relative proportions of the different parts of an object as related to the whole.

The divisions made by vertical, horizontal and oblique lines will greatly aid the pupil in his work. He is thus enabled to become methodical and accurate in his measurements, and will cultivate what is known as the “true eye” for drawing.

Do not, however, encourage the pupil to depend on or permit himself to be crippled by the constant application of mechanical methods or appliances, or allow the use thereof to interfere with free-hand drawing. They are intended for occasional use. To avoid this, have him frequently lay aside the guide line methods and trust more to the eye.

Whenever desirable, more divisions can easily be made. The additional spaces need not be made over the entire surface, but the surface may be subdivided indefinitely in whole or in part, according to the intricacy of detail in the design to be copied, same size, enlarged or reduced.