Color database (X11.3) on Sun vs HP

[steven.mikes]

I have a single rgb.txt that I use on a Sun3 and an HP 9000/350, both on
X11.3, yet my application displays different colors for certain values.

Is this because of some color frame buffer hardware quirks or something
else?  The basic problem seems to be that for certain colors, the
foreground color is inverted with the background color on one or the other
system using the same rgb.txt values and running the same application.