[argyllcms] Re: problems hitting white point (color temperature, RGB gain/contrast) while maintaining brightness: dE not stable

  • From: Nikolay Pokhilchenko <nikolay_po@xxxxxxx>
  • To: argyllcms@xxxxxxxxxxxxx
  • Date: Thu, 10 Dec 2009 17:40:35 +0300

David Heinrich wrote:

> So even with the CRT in Standard Mode, doing fine-adjustments I still can't
> get too great. The problem is still similar to what I quoted in the original
> e-mail: when adjusting R, G, and B channel gains individually, the dE's
> bounce around as does the recommendation of which values to change.

David, did You try to lover Your target brightness by 2-3 cd/m^2? If one or 
more channel gain levers are at their maximums, it may help.
This is a typical problem for some displays. There may be rather large steps of 
per-channel gain, so it's impossible to achieve the desired white point by 
hardware. With some displays I've got a best difference about 2.3dE or even a 
bit worse. The calibration can correct such deference.

> Is there
> a way to change how long the Spyder2 takes readings before updating? It
> would seem that if there was a way to get the program to average the results
> of 5-10 updates or 5-10 seconds (I'm not sure how this works: is argyll
> getting a reading from spyder2 every several seconds, or is it averaging the
> readings of spyder2 over several seconds?), it would smooth out this stuff
> and allow for me to get a better idea as to what to do on my display.

I'm just changing one channel by one step, waiting 5 seconds and looking is the 
difference less or more. Then I'm tuning the next channel. Repeat.
Sometimes I didn't see at the dispcal recommendations at all.

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