How to use an editor’s proportion scale in one easy-peasy lesson
(Ross Collins, associate professor of communication, North Dakota State University)

Directions below cover photo proportioning for editors and designers using the old-fashioned method from pre-Photoshop days. Alas, another example of things I learned that are now nearly obsolete, but you still do encounter proportion wheels, and so it is handy to know the principles, as described below.

Note: these scales are available on line, at most art supply stores, and university bookstores.They are disc-shaped plastic, hence their nickname, proportion wheel. They usually cost about \$5.

1. Measure the art to be scaled, in inches, from crop marks. Jot down the size.

2. Measure the width (usually) or depth of space the scaled photo must match. Jot down the size. If you are scaling to standard column sizes, refer to your publication's headline schedule or design sheet for standard measurements. Convert picas to inches: 6p=1 inch.

3. Find the width of the original photo on the inside scale of the proportion wheel, the scale labeled "Original Size."

4. Match that width with the width of the desired reproduction size on the outer scale, labeled "Reproduction Size."

5. Holding the wheel at that point, find the depth of the original art on the inside scale.

6. Read directly across to find the reproduction depth on the outside scale. Jot down the size.

7. Read the percentage reduction (or occasionally enlargement) in the window at the center of the proportion wheel. Jot down the percentage.

Example: Original photo is 8 x 10, horizontal format (that is, 10 inches wide, 8 inches deep).
Reduced photo must fit a space 6 inches wide. Write:

8 x 10=
? x 6

? %

Line up 10 on Original Size scale with 6 on Reproduction Size scale.

Holding that line-up, look over to 8 on Original Size scale. Corresponding size on reproduction scale is 4 13/16. Percentage of original size is 60 percent.

So:
8 x 10=
4 13/16 x 6

60%