These settings are similar to models "7" and "8", except that the background color will be gray instead of white. This is useful if you want to use 3-D-LINES and want to eliminate intensity considerations.
Equivalent settings
Color-Model "9" is equivalent to Color-Trans "3", Intensity-Flags "193".
Color-Model "10" is equivalent to Color-Trans "1", Intensity-Flags "193".
See Book 4, Appendix H for details.