reinoud@duteca (Reinoud Lamberts) (07/31/90)
The new Apple 8/24 Display Card in my Mac II shows a color shift when it is
switched between 24-bit (millions) mode and any other mode. Colors are
displayed just a little more red in 24-bit mode. This is most clearly visible
on large white and gray areas, with low screen brightness. I am using the Apple
13 inch color monitor.
This color shift seems a bit strange to me. If it is intentional, to correct
for the high color temperature ('blueness') of the CRT, then why in 24-bit mode
only? If it is unintentional, then maybe they have used different DAC's or
gamma correction methods for different modes. This seems unlikely to me,
because it would mean duplicating functionality on an already expensive chip.
Has anyone else noticed a color shift when switching modes on an 8/24 Display
Card? Does anyone have an explanation for it? Is there documentation available
on the 8/24 Display Card? I would really like to know what is happening. Thanks
for any information!
Reinoud Lamberts
mail me at: reinoud@duteca.tudelft.nl
PS Programs writing directly to screen often run into trouble on an 8/24
Display Card, because it presents a NuBus super slot space address as its
BaseAddress. Programs, running normally in 24-bit addressing mode, can't acces
this 32-bit address correctly.