A print scale, sometimes also called a step wedge, is a darkroom tool that can make your workflow more consistent and efficient. A step wedge is functionally similar to a print scale but has a slightly different purpose.
Normally to determine the proper exposure of a print you make a test print. This is done after you frame, focus, stop down the enlarger lens, and turn off the not-safe lights. You’d then get a piece of light sensitive paper and a board. You’d set the timer for 1