[argyllcms] Re: Fluorescent patches in a profile target?
- From: Ben Goren <ben@xxxxxxxxxxxxxxxx>
- To: argyllcms@xxxxxxxxxxxxx
- Date: Tue, 23 Mar 2010 06:11:41 -0700
<tap> <tap> <tap> Testing, testing. One, two, three. Test, test, test.
Cheers,
b&
On 2010 Mar 20, at 8:44 AM, Ben Goren wrote:
> Hello (Hello (Hello?)?)?
>
> Is there anybody out there?
>
> Cheers,
>
> b&
>
> On 2010 Mar 18, at 8:22 PM, Ben Goren wrote:
>
>> I'm still working on a less-un-ideal target for profiling cameras, and I've
>> been thinking about things a lot.
>>
>> I've recently realized, in one of those mind-twisting kinds of ways, just
>> how many things in a typical photographic scene are likely to be brighter
>> than a 100% reflective target (such as the Tyvek I discovered or the PTFE
>> that Ernst is collecting data on). Of course, there're emissive objects and
>> specular reflections...but there're also fluorescent objects. Some cheap
>> office papers, for example, have OBAs that push the short-wavelength
>> brightness well over 100%. I haven't gone searching for any DayGlo things to
>> check, but it wouldn't surprise me if some of them have peaks over 100% (at
>> different wavelengths, of course) as well.
>>
>> Adobe Camera Raw, with its flattest settings and the ``Camera Faithful''
>> color profile is actually a not-too-miserable colorimetric match for a
>> scene, provided you start with a correct incident exposure and apply the
>> proper white balance. The caveat is that a 100% white target will get
>> rendered as L* = 90 (or thereabouts) and the rest of the highlights will be
>> scaled accordingly. I haven't tried to determine the shape of the curve;
>> instead, I've just been using the results as a starting point to feed to
>> Argyll.
>>
>> I'm therefore wondering about the wisdom of including fluorescent patches in
>> a profile target in an attempt to characterize the 100%+ range.
>>
>> Obviously, different lighting conditions will produce different amounts of
>> fluorescence. I mainly intend to use this target with studio strobes, which
>> I hope have a similar enough spectrum to the illumination source in an i1 to
>> produce useful results.
>>
>> But I'm also wondering about how well Argyll would deal with the math...as
>> well as, of course, whether or not it's even a good idea in the first place.
>> And, if it *is* a good idea, what kinds of fluorescent materials to look
>> for....
>>
>> Thanks,
>>
>> b&
>
>
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