Copy Protection: Red Filter
In order to make photo copying more difficult, some games printed the copy protection chart or lookup information with light blue ink overlaid by red ink patterns to obscure the text. This made the information difficult to see and read and would usually produce an illegible image with black & white copiers or scanners of the era. To read the page, a red filter was included with the game which filtered out the red patterns making the underlying text legible.
Copy Protection: Red Filter is part of the tagging category Copy Protection.