Default Color Sets (IM: XO)

Inside Macintosh: QuickDraw GX Objects /: Chapter 4 - Colors and Color-Related Objects / About Color Set Objects

Default Color Sets
QuickDraw GX maintains several default color sets, one for each possible pixel size in bitmaps that use indexed space--1, 2, 4, and 8 bits. (Bitmaps with pixel sizes over 8 bits cannot use indexed space.) When you create a bitmap with a pixel size of 8 bits or less and specify nil for its color set, QuickDraw GX uses the appropriate default color set whenever you draw that bitmap.
Each of the default color sets consists of a gray ramp, using color values in gxGraySpace that progress in order from white at an index value of 1 to black at
the highest index value. For a pixel size of 1 bit, for example, the default color set consists of two colors: white and black.
You do not create a copy of any of the default color sets by calling the GXNewColorSet function; that function requires you to supply a specific array of color values.
You can inspect and change any of the default color sets by using
the GXGetDefaultColorSet function, described on page 4-62, and the GXSetDefaultColorSet function, described on page 4-63. Bitmaps are described
in the bitmap shapes chapter of Inside Macintosh: QuickDraw GX Graphics.