This program tests for scotopic sensitivity. It will also permits you to print overlays with transparency film for overhead projectors.
To use the program, press the colored squares to compare colors, when you obtain a color that you want to print press the "share" button. You need to press the share button twice. Once to create the image and the next to "share" it.
The user needs to have a printing program available to print the overlay. The overlay can be e-mailed to a persona and then printed. Some printers will not print on a transparency so check your printer.