[argyllcms] Re: Ideal camera target
- From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 2 Feb 2010 17:34:17 -0700
On 2010 Feb 2, at 5:27 PM, Gerhard Fuernkranz wrote:
> Ben Goren wrote:
>> I'll be sure to bring the i1 with me to the fabric store to make the
>> selection, but the real test will be in photographing the trap. If the
>> black levels of the trap are comparable to those when shooting with the lens
>> cap on, it should meet the ``good enough'' test.
>>
>
> Well, the fact that a black trap is a very dark object in the captured
> scene still does not imply that it won't suffer from veiling glare.
Certainly.
But I think it will still serve two very important purposes. First, if it
isn’t awfully darned close to R=G=B=0 in the image the camera captures,
you know you’ve got a problem somewhere. And, second, assuming you
don’t have any (significant) problems, it provides an anchor for the
profiling software to use for its black point -- there shouldn't be any further
need for extrapolation.
It's for similar reasons why I'm planning on including a flash-backlit patch
(which should result in saturated pixels in the captured image): to provide the
absolute white point as a reference, rather than relying on the whiteness of
the paper the target is printed on as a proxy.
Cheers,
b&
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