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

[Joshua D. Boyd]

On Fri, Aug 22, 2003 at 01:02:52PM -0400, Curtis H. Wilbar Jr. wrote:
> All this is logical... however, once processed, the difference in 
> display on a 24 bit display vs a 32 bit color dispaly is probably
> imperceptable.... and didn't this whole thread start on what the
> display was displaying... not what amount of significant bits were
> used in processing ??? or is my memory dropping bits ?

A 24bit per pixel display and a 32bit per pixel display are virtually
always the same thing.  The 32bit per pixel display is still only
feeding 24bits per pixel to the RAMDACS, so of course the difference is
imperceptible, because there is no bloody difference.

If you mean a 24bit per pixel display versus a 32bit per channel display
(96 bits per pixel), then the difference is NOT imperceptible in all
cases.  24 bits per pixel is only arguably enough if the 24 bits is
evening spread across the entire dynamic range of the image.

Look at this picture:
http://www.celestrion.net/~jdboyd/test.tiff
It doesn't take a particularly good eye, or a particularly well
calibrated monitor (set your contrast all the way up, and play with the
brightness), to make out the stripes, which are caused by having only
24bits per pixel for display rather than more.