The Overlay Comparison feature allows to customize the colors of the 2 documents that are being compared. The colors are be remembered when the "Compare Overlay" dialog is closed. When changing from the default colors, we suggest using complementary colors when comparing PDF documents using the Overlay Comparison feature in jPDF Editor. Complementary colors are colors that add up to black which will ensure that the common elements on the two drawings / documents are displayed in black (overlay of the 2 complementary colors).
Using RGB (Red, Green, Blue) values, complementary colors are colors that add up to (255, 255, 255). See below for a few color pairs of complementary colors. The number in parenthesis represent the color in RGB values.