[argyllcms] Re: Number of patches - well behaved printer?

  • From: Rishi Sanyal <rishi.j.sanyal@xxxxxxxxx>
  • To: "argyllcms@xxxxxxxxxxxxx" <argyllcms@xxxxxxxxxxxxx>
  • Date: Thu, 24 Feb 2011 15:08:10 -0800

"Alternatively, profiles done from targets shot using different exposures are 
in wide use; operator just selects the proper proper profile based on visual."

Really? What software packages use this principle? Not Adobe products, or 
digiKam, or RPP from what I know... I'm curious!

Rishi

On Feb 24, 2011, at 5:53 AM, Iliah Borg <ib@xxxxxxxxxxx> wrote:

> Dear Martin,
> 
> 
> On Feb 24, 2011, at 8:27 AM, Idea Digital Imaging wrote:
> 
>> On 24 Feb 2011, at 12:30, Iliah Borg wrote:
>> 
>>> But of course, chart is on the film. Reproduction here is of a physical 
>>> object, that is why we are operating measured values, not the desired 
>>> values. So, in your words - "the chart on the film" is the subject of 
>>> reproduction. This allows to approximate how the particular film responds 
>>> to the light.
>> 
>> 
>> How useful are the results of this process?
>> 
>> I looked at trying to profile negatives on our drum scanners more than a 
>> decade ago but the results were very poor.
>> 
>> You could build a good profile from a correctly exposed test image but 
>> variations in over/under exposure in real world images rendered the profiles 
>> useless.
>> 
> 
> With input profiles for "moving target" media like film or digital captures 
> (moving in the sense they depend on the colour of light, exposure, 
> development, aging, etc) the task of the profiles is to convert colours, just 
> colours - not the tone. Ironically, even auto-levels before applying a 
> matrix-based profile do a better job than an elaborative hand-edited LUT 
> profile with an embedded tone curve.
> 
> Alternatively, profiles done from targets shot using different exposures are 
> in wide use; operator just selects the proper proper profile based on visual.
> 
> 
>> And, as you also need to incorporate a wide choice of print papers into 
>> colour managment, I didn't really see how profiling would be faster or 
>> better than having a good scanner operator getting the colour right during 
>> scanning?
> 
> I do not see how papers come into the blend. Applying output profiles is 
> accomplished in a much later stage. Input profiles are helpers, they cut the 
> time an operator spends working on an image; but most importantly they lessen 
> the fatigue.
> 
> --
> Iliah Borg
> ib@xxxxxxxxxxx
> 
> 
> 
> 

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