This commands allows the user to change the colour used to represent the ``masked-off'' elements in the DEFINE MASK and DISPLAY MASK options. The user is prompted for the colour to be used. e.g.
COLOUR FOR MASKED OFF ELEMENTS [RED]:? Enter one of the following available colours: BLACK BLUE BROWN CYAN GREEN GREY MAGENTA ORANGE RED VIOLET WHITE YELLOW (0 INDEX) (1 INDEX) COLOUR FOR MASKED OFF ELEMENTS [RED]:green
When the data and mask are next displayed the chosen colour will be used to display the ``masked-off'' elements. (In fact the colour will be as close as is possible, given the colours presently stored in the colour table.)