The color used by the FM Hue Test is reproduced (approximately) on the screen to aid data input and the analysis of polar and linear graphs. However, if the computer being used is unable to display all the colors, color dithering is used. This can reduce the legibility of the cap numbers on the data entry screen.
If this occurs, color can be disabled from the Preferences option which is accessed from the Edit menu. The caps on the input screen are then displayed in grey and color labels are added to the graphs.