Numbered 1-12, 1/2" x 5" in length. Quality control reflection guide for the exposure and development of line negatives & positives and checking camera focus.
Numbered 2-21, 1/2" x 5" in length. Quality control scale that helps the user determine and standardize the proper exposure and processing of photo sensitive materials. Used with litho plates, silk screen stencils, printed circuit boards, film positives, photo print papers and more.