[Openicc] Manual profiling

Hal V. Engel hvengel at gmail.com
Sun Apr 3 11:18:52 PDT 2011


On Saturday, April 02, 2011 09:36:50 AM Alexandre Prokoudine wrote:
> On 4/2/11, Richard Hughes wrote:
> > Your advice please: Is manual profiling useful for people too poor for
> > a hardware calibration device or is worse than useless?
> 
> I was asked about manual profiling just few days ago when I blogged on
> G-C-M. I meet people who need it every once in a while. Isn't
> something like LProf's manual profiler possible?
> 
> Alexandre Prokoudine
> http://libregraphicsworld.org

Most of the mid-gray box gamma tools don't work very well as most of them will 
vary +- 0.2 gamma on repeated tests.   This is enough to make these tools 
close to useless.   In LProf I use the gamma tool from Norman Koren's web 
site.  See:

http://www.normankoren.com/makingfineprints1A.html

My experience is that this is way more consistent than any of the others I 
tried and repeated tests are consisant to about +- 0.05 gamma which I think is 
very good for a visual tool like this.   The results from this are very close 
to those obtained using a measurement device.  In addition this also allows 
for adjusting the black level of the monitor.

I got explicit perission from Norman to use this in LProf so you will need to 
ask him before using it in GCM.  I suspect that he will not have a problem 
with it.

Also in LProf I have this setup to allow users to set the gamma for the 
individual channels (red, green and blue). 

Hal
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