On Saturday, July 19, 2014 10:29:56 AM UTC-7, N_Cook wrote:
On 19/07/2014 16:35, William Sommerwerck wrote:

"N_Cook" wrote in message ...



I had tried dropping back to 16 bit colour but the same "1 bit"
saturation effect on a test colour bar image.

Win7 is ok,ignore previous, the problem is with XP , happens to be Pro
version, not showing the Hz settings.

Perhaps the screen is organized with an incompatible setup to your bar-generating
program? Right-click on the program, and see if there's variant video settings
available (there's some version-to-version variation in the video settings matrix,
a type that has been outmoded gets ditched in favor of settings for a new
high-res screen sometimes). In this scenario, the 'black' parts are addressing
into uninitialized memory on the video card.