On Thu, 20 Jun 2002, Christoph Koulen wrote:

> To my knowledge, a monitor is an analogous device, that can potetially
> display _any number_  of intermediate shades of each primary colour.
> 
> Isn't the RAMDAC (Digital-Analog Converter) the chip, that converts a
> digital value (i.e. a 10bit color value) into a voltage that ultimatly
> drives the intensity of each of the monitor's color guns? I cannot see a
> reason, why a color gun wouldn't respond to any intermediate voltage
> level. If it weren't driven by a RAMDAC of inherently limited resolution
> but a power supply capable of outputting a continuous voltage range...

A CRT is theoretically continuous, but as I understand it most LCDs
have a fixed number of distinct colours.
Many monitors have digital processing circuitry to improve the consistency 
of the picture, so the continuous nature of the color is lost at that 
point.
 
> The delimiting factor, I agree, would be the human eye! I wonder, if it
> is capable of distinguishing between 1024 shades of a primary color?

Probably not, especially since there are colours too bright and too dim
for a monitor to show. However with only 256 shades the steps between 
adjacent colors are not always even (gamma mapping can reduce this problem)
and it isn't difficult to find single steps which are very obvious,
especially on a gray ramp. 1024 shades makes it easer to make the steps
even, and maybe allow all of them to be invisible.

-- 
Dr. Andrew C. Aitchison         Computer Officer, DPMMS, Cambridge
[EMAIL PROTECTED]   http://www.dpmms.cam.ac.uk/~werdna

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