[argyllcms] Digital Camera input profiles and gamma correction.
- From: Paul Hunt <prhunt@xxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Sun, 12 Apr 2009 20:20:47 +1000
When building camera input profiles, why is it necessary/recommended that the
photo of the IT8.7/2 target be gamma corrected?
I am trying to better understand my observations following camera profiling
using gamma-corrected and non gamma-corrected target photographs.
Profile made from gamma-corrected target image = relatively low delta-E
Profile made from non-gamma-corrected target image = relatively high delta-E
Profile made from gamma-corrected target image - photos processed using this
profile in ufraw appear "correct" when ufraw gamma is set to 0.45. Images
look "linear" (dark and left-skewed histogram) when ufraw gamma set to 1.
Profile made from non-gamma-corrected image - photos processed using this
profile in ufraw appear correct when ufraw gamma is set to 1. Images look
washed-out when ufraw gamma is set to 0.45. (It therefore like the profile
itself is providing the gamma correction).
I'd appreciate any comments that will help improve my understanding.
Paul
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