[argyllcms] Re: help with camera profile

  • From: Stephen T <stwebvanuatu@xxxxxxxxxxxx>
  • To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
  • Date: Fri, 20 Jul 2012 05:30:08 -0700 (PDT)

Colour is critical but most raw photo software developers focus on whimsical 
image processing algorithms.

The original colour matrix profiles in dcraw are terrible. Canon's proprietary 
output is inaccurate. I have made my own matrix profiles and the results look 
better. Now people ask: how did you get the blue sky colour right? With a 
simple 3x3 linear matrix transform.

Raw Therapee has some custom DCP profiles that are reasonably good and your 
camera might be supported. They are based on the CC24 and seem to behave like 
matrix profiles.

Once you have a profile that is conforms to the CIE standard observer, you then 
need to sort out your work flow, especially (working space) RGB tone curves 
(not available in ufraw). If you want to tweak and enhance the colour further, 
that's best done in the RGB working space.

So yes, much of my profiling troubles were due to inadequate software and a 
poor work flow!


 From: edmund ronald <edmundronald@xxxxxxxxx>
To: argyllcms@xxxxxxxxxxxxx 
Sent: Friday, 20 July 2012 7:58 PM
Subject: [argyllcms] Re: help with camera profile

If you *need* camera profiling for a modern camera, there is probably something 
wrong with your workflow or with your camera.

My humble suggestion as a practising photographer would be to forget about 
"real" camera profiling in anger unless you really MUST do it. MUST means that 
you do this professionally for a manufacturer, have an older camera that is 
painful to replace, or reproduce artwork, products or fashion. 

A need to profiling very often leads to a need for profile editing which opens 
another can of worms and necessitates very precisely calibrated screens to be 

If you MUST do it, then I would recommend first finding a Raw converter that 
plays well with user profiling, eg. some dcraw descendants such as RPP which 
has Argyll embedded anyway, the horrid but  extremely useful dcraw itself, 
Capture One, Adobe Lightroom and Photoshop ACR and of course Iridant's 
beautiful mac-only  Raw Developer. 

Chances are you will find decent canned profiles for your camera for all of the 
above. However if your light is exceptionally strange or you camera is whacked, 
there is a small cheap object made by Xrite called a Colorchecker Passport 
which is a target especially designed for carrying around for profiling on 
location. The advantage of this is it that it is designed to be carried around 
photographed by normal unskilled human beings (I helped specify it to that 
end), and also very useful for visual assessment of the results. 

And, although you will find me patronizing, all of you being technically gifted 
high IQ individuals, I do reiterate that the need for camera profiling and in 
particular the apparent inadequacy of a simple matrix profile are usually signs 
of bad workflow or extreme expectations. 


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