[rescue] Re: SGI Onyx4 - uses ATI graphics chips (sigh)

Peter Corlett abuse at cabal.org.uk
Thu Aug 28 19:53:24 CDT 2003


Joshua D. Boyd <jdboyd at celestrion.celestrion.net> wrote:
> On Fri, Aug 22, 2003 at 08:14:57PM -0700, Lionel Peterson wrote:
>> I would test that theory by having a field of one color (say all red, in
>> my example FF 00 00, for Red, Green and Blue), and in that filed, draw a
>> solid image of, say, a circle with a color that is one bit off (say FE 00
>> 00) - if you can see the image, you can resolve the difference - if you
>> can't, you can't.
> In my experience, something like F0F0F0 versus F1F0F0 would be likely to
> be more visible.

That's because the DACs in video cards are normally linear, but your sense
of vision is logarithmic. So 404040 -> 808080 will appear to be the same
sort of jump as 202020 -> 404040.

It's also possible that your monitor and video card combination will clip
the extremes, either just because of poor adjustment, or by design.

-- 
>> That will happen 2 weeks after pigs fly.
> I hear the government has funded a jet-pig initiative...
Well, thats one way for the politicians to justify more pork in the budget.
					- Various in alt.folklore.computers



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