COLOR_MODEL settings 5 and 6 create a reverse-video image of your application. Thus, low-intensity white-on-black will appear as black-on-gray, and high-intensity will appear as black-on-white.
These settings cause the intensity to appear in the background instead of the foreground. For applications that have low-intensity legends and high-intensity data fields, this will cause the data fields to be highlighted on the screen.
COLOR_MODEL 5 is equivalent to COLOR_TRANS 1, INTENSITY_FLAGS 129.
COLOR_MODEL 6 is equivalent to COLOR_TRANS 1, INTENSITY_FLAGS 129, BACKGROUND_INTENSITY 2.