Quantum Data 801GC - Manual (Page 45)

4-7
BLU_PIC, GRAY_PIC, GRN_PIC, RED_PIC,
WHT_PIC, Flat, Flat Gray, Flat_B, Flat_G, and
Flat_R
Description A solid blue (BLU), gray, green (GRN), red, or
white (WHT) box fills the active video area.
Only the white fill has a secondary version. It can
be changed to a black fill.
Test Purity adjustment
Purpose To produce correct colors in a displayed image,
the electron beams from each of the three (3) guns
in the CRT should strike only their matching
phosphors. A white image shows patches of various
colors on a monitor with bad purity. The purity
adjustment(s) should be performed before doing
any brightness or color tests. In some cases, purity
adjustments involve loosening and repositioning
the yoke, in which case purity should be adjusted
prior to doing any geometry tests.