Re: Digital Camera Profiling
Re: Digital Camera Profiling
- Subject: Re: Digital Camera Profiling
- From: Igor <email@hidden>
- Date: Mon, 24 Sep 2001 23:29:27 +0200
Neil Snape wrote:
>
The idea is rather to describe the type of colours the camera sees and
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not to
>
profile for the chart, scene or what have you.
What is 'type of colours'? Are you refering to gamut?
Terry Wyse wrote:
>
As Mr. Snape stated, I have to believe that profiling a digicam is
>
simply
>
characterizing the combination of the CCD, light path, light
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temperature and
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capture software settings, nothing more.
The first difficulty is this: Colour is the result of the reflection of
light on a surface (I'll leave out filtering, for the sake of
simplicity). Wich means there are basicly two variables involved: light
and surface. The process of profiling is aimed at matching colours on
two different surfaces in the same lighting conditions. The variable of
light is ruled out by defining a whitepoint. In these highly controlled
situations it is very well possible to make a good profile of any given
piece of hardware. But in real life (as often caught in photography) the
conditions are simply not that much controlled. The mere fact of
capturing 3-d information in 2-d media, is adding so much complexity
where it comes to colour, that a profile is rendered useless.
The second difficulty is that in real life our colour perception is very
much controlled by the effects of colour constancy. As far as I can
tell, these effects have NOT been taken into account in the process of
profiling. I'm just about to publish some webpages on the subject. You
can expect this page on colour constancy:
http://www.colourjinn.com/6oncolour/relativity/colourconst/colourconst.html
to be available within a few days.
Profiling does wonders in a controlled situation, but ONLY in a
controlled situation. As others indicated: the more control, the better
use of a profile. Ever wondered why this list is mainly visited by
graphics specialists? After all, there are many more trades involved in
colour. But graphics can be viewed in controlled lighting conditions and
have only two dimensions.
I can imagine a camera profile doing some good in very controlled studio
environment. But even then, the use of it is far more limited than the
use of a scanner profile. Scanners and camera's are basicly apples and
pears when it comes to colours.
Nevertheless: after the image is captured, then profiles of monitors
etc. are VERY important to be able to review, adjust and multiply the
image.
Igor Asselbergs