Datacolor User to User Support Group.

--- In colorvision_group@yahoogroups.com, "Brian Smith" <zen1@...> 
wrote:
> 
> Contrast is definitely not gamma. 

Oh Yes! Gamma and Contrast are intricately linked. Your display (any 
display) has got a native gamma that describes the way it is reacting 
to incoming signal. The software gamma that is applied to a signal 
supposed to be shown on that display is there to compensate for the 
non linear gamma curve of the display that would otherwise alter 
the "natural" contrasts of your picture

Now again, the confusion comes from the use of the wrong terminology 
for the two tweaking knobs on your display: "brightness" 
and "contrast". As said before, "brightness" relates to black level 
(and as such it will have a direct influence on the contrast of the 
picture). "Contrast" is brightning or darkening your white point 
hence it is having an influence on the overall brightness of the 
picture which shows the non sense in the choice of terminology...

  
> I don't believe that an observer is capable of making absolute 
> luminance judgements.

Of course not, since luminance judgement is subjective and varies 
from one viewer to the other and with ambiant light. Which is why I 
don't quite see the use of being able to set your black and white 
point luminance value in Candela unit in the Spyder Pro software 
version. How do these candela setting relates to the viewer assesment 
of display luminance?


>The contrast should be adjusted for the comfort

Yes but again, it is not the contrast that has to be adjusted for 
comfort, it is the pedestal and the white point luminance