Re: scanner profiling (again)
Re: scanner profiling (again)
- Subject: Re: scanner profiling (again)
- From: email@hidden
- Date: Wed, 17 Dec 2003 11:32:30 -0500
>
> I don't understand why scene content would matter in this case. As I
>
> said, the target contains patches corresponding to highlight and
>
> shadow. So any scene's content should be covered by the target
>
> patches.
I'm a longtime lurker to this list as I slowly try to become more color
savvy, but if I'm following this particular issue correctly, it is one for
which I might be able to add something useful.
If you take a camera, any camera, and photograph a target, you cannot use
the target for either bp or wp as they apply to every content situation.
For example, if you are shooting chrome, the nature of the material will
reflect your source lights directly back into the lens, which would then be
the brightest thing in the scene. In fact, if you had your target in frame
at that moment, you would see in your chrome/monitor, that the highlight in
the chrome is much lighter than the white patch of your target. It would
also be true if you had anything emitting light in your scene, since the
target is not an emitter but a reflector.
The same thing applies to shadows. If you are shooting wrinkled black
velvet, you will get shadow areas that are far darker than the darkest patch
in your target, because they are going to reflect much less light back into
the lens than the dark patch in your target.
Targets are an excellent way to find the gray point, but lousy for bp and wp
if you are talking about shooting one with your camera. This does not
negate their usefulness in scanner profiling, because chromes cannot emit
light, nor create the kind of zero reflectance/transmittance of wrinkles in
black velvet. By their nature chromes and negatives behave much more like
targets than the photographed "real" world.
So, that's my take on this issue. Hope it helps.
Tim Lennox
retoucher and prepress specialist
E & B Giftware, LLC.
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