Gauging proportions is as simple as making sure that the width and height of the objects in your drawing are proportionally similar to those in your reference. Believable art starts with correct proportions, so learning how to gauge proportions accurately will be invaluable. You don’t need to know the actual inches or centimeters; instead, measure the relative sizes of the elements to achieve an accurate representation of your subject.
There are many tools available for gauging proportions, from a simple pencil to tools made specifically for measuring, such as sewing gauges or dividers. Dividers, both standard and proportional, are used to gauge proportions of two-dimensional reference materials, such as photographs, rather than of three-dimensional objects, such as those in a still-life setup. Proportional dividers enable you to enlarge or reduce by measuring the reference with one end of the tool and then using the other end to determine the size of the image in your drawing.
Proportioning can be done loosely for a quick sketch or more precisely for a finished drawing. The subject also influences how accurate the drawing needs to be. You may be less concerned about the proportions of a tree than you are about the proportions of an automobile.
Gauging Proportions With a Pencil
Gauging Proportions can be done by “measuring” each part of the subject with a pencil. Use the top of your thumb to make the distance from the end of the pencil. Now compare this measurement with those of other parts of the image. In this example, the teapot’s height is equal to its width.
Lock in Accurate Proportions
To correctly gauge proportions in this manner, lock your arm straight in front of you, holding the pencil straight up. Look at the pencil and the subject you’re measuring through one eye. A bent arm may result in inaccurate measurements because you may bend your arm at different angles from one measurement to another.
Using Standard Dividers
Measure the subject in your reference with the dividers and transfer the length to your surface. You can only measure a one-to-one ratio with standard dividers. If you wanted to enlarge this window to twice its size, you would have to double the divider’s measurement.
Using Proportional Dividers
Proportional dividers are used not only to compare proportions but also to enlarge or reduce. Measure the subject in your reference with one end of the dividers, then use the other end to mark the measurement for your drawing. The notches in the center of the dividers let you determine just how much you want to enlarge or reduce the size of the image.
Using a Sewing Gauge
Align the edge of the object with the end of the sewing gauge, then move the slider up or down to mark the other edge. Transfer that measurement to your drawing
