[argyllcms] Re: Monitor screen color unevenness/irregularity

  • From: Graeme Gill <graeme@xxxxxxxxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Tue, 17 Apr 2012 00:22:49 +1000

Alexey Blinov wrote:
> I measured color on different places on a fully white screen. When visualized 
> on the CIE 1931
> x,y plane, I got an area of size around 0.01. The distance between two 
> closest shades of white
> (255,255,255 and 254,255,255) is around 8e-4. Accuracy of the colorimeter, 
> i.e. the diameter of
> the smallest circle enclosing many measurements of same color at same place, 
> is around 4e-4.
> So, variations of color on the screen is around 10 times more than the 
> variation due to limited
> (8-bit per channel) digital representation. Who measured such unevenness of 
> professional
> monitors, could you post your results?

        spatial color unevenness in screens is a quite well known display 
defect. One of
the specifications of higher quality screens is improved spatial screen 
and many of these displays take technical measures to ensure uniformity, such
as spatial calibration systems.

(I'm not sure x,y values are a good way of evaluating non-uniformity, since they
 do not correlate to visual differences. Delta E is a better measure in this 

There are various industry standard methods and thresholds for display 
measurement, such as VESA and ISO standards.

Graeme Gill.

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