Re: digital camera profiling
Re: digital camera profiling
- Subject: Re: digital camera profiling
- From: "Fleisher, Ken" <email@hidden>
- Date: Wed, 20 May 2009 13:33:56 -0400
- Thread-topic: digital camera profiling
On 5/20/09 11:52 AM, "Marco Ugolini" <email@hidden> wrote:
> Ken Fleisher wrote:
>
>> The main problem is the spectra of the colors on the control strip
>> are not the same as the spectra of the pigments in the artwork.
>
> But the goal in this case is a metameric match, not a spectral match.
>
> If you are interested in spectral capture, on the other hand, then you ought
> to look at the ongoing work by Roy Berns:
> <http://www.art-si.org>
>
> Marco
Hi Marco. It's true that the goal is colorimetric matching, not spectral
matching, but the problem I described is the "cause" of the color errors
that are experienced when 1) calibrating to a ColorChecker SG and then
photographing artwork who's pigments do not span the same spectral gamut as
the target colors AND 2) when the camera's spectral sensitivities are not a
linear transform of the color matching functions (which they are not for the
cameras listed). One solution to that problem is to use a reference target
that is composed of the same materials as the object that you are capturing.
Another solution is to use a camera with more than three broad-band
channels, which can mean many spectral channels, or as few as 5-6 might be
adequate for colorimetric imaging.
Thank you for the link--I am familiar with Dr. Berns' research.
Ken
--
Ken Fleisher
Photographer
Imaging & Visual Services
National Gallery of Art
Washington, D.C.
Phone: (202) 712-7471
email@hidden
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