"Q-13 / Q-14 Gray Scale is a quality control device that helps compare tone values of reflection copy with its reproduction. Also helps find the correct exposure and processing conditions. Balances negatives and positives in a color reproduction process and plots tone reproduction curves. Each packet contains: One set of Color Control Patches (nine-patches that includes - Two saturations of each patch, one Gray Scale (20 steps in 0.10 density increments between 0.0 [white] and a practical printing black of 1.90 density), and one Separation Guide. Separation Guides are used as the set up guide to calibrate several digital color print systems. In addition, helps photographers compare the color of the subject with known printing colors. Also helps Graphic Arts camera operators identify separation negatives and positives for color reproduction processes."