Re: B+W 77mm UV/IR Cut (486M) MRC Filter
Re: B+W 77mm UV/IR Cut (486M) MRC Filter
- Subject: Re: B+W 77mm UV/IR Cut (486M) MRC Filter
- From: Ben Goren <email@hidden>
- Date: Sun, 26 May 2013 08:25:50 -0700
On May 26, 2013, at 7:25 AM, Hal Hinderliter <email@hidden> wrote:
> which type of studio lighting emits the least IR? (LED?) But what about UV, isn't that more important to reduce at the light source?
A good profile made in the same light with a good target that's been measured with a good spectrophotometer will take care of the IR. Even if your camera is sensitive to IR (and anything you'd be likely to buy today already has good IR filtration), the profile should take care of pushing the luminosity of those super deep reds where they belong -- which is outside of your printer's gamut anyway (besides being invisible to humans).
If UV is a problem, filtration is useless. That's because, if the artwork you're photographing is fluorescent, you're screwed; you can't print it, and the original is going to look significantly different in whatever light it's being viewed in -- it's the ultimate form of metamerism (though with different physics at play). There're similar problems with metallic and iridescent paints; there's just nothing you can do.
If it's for a commercial giclee job, tell the artist about the problem up front (or as soon as you realize that the work is fluorescing, which you should probably be checking with a black light at the time you accept the piece). Discuss what can be done...which is basically pretending the problem doesn't exist at your end at first and hoping for the best, doing some Photoshop adjustment to make the color come out to some agreed-upon compromise in the print if that's not good enough, and having the artist (or an assistant or whomever) hand-apply the original pigments over those portions of the print. Note that the light used for comparison when the artist comes to review is critical; be sure to show the two side-by-side not just in your normal viewing conditions, but under regular (cheap) tungsten and actual outdoors sunlight as well. If the print is to be displayed in certain lighting conditions, if you can photograph the art in those conditions *and* get a measurement of them with a spectrophotometer, you can make a pretty good match...but it'll be a bad match in any other conditions.
If it's for conservation purposes...ship it somewhere that they do multispectral imaging with a spectroradiometer that reaches into UV. Nothing else is going to work. See Dr. Berns at art-si.org for more.
(If the artwork isn't fluorescing, UV is irrelevant. Not only is it invisible to humans, your profile, if made in the same light, etc., will take care of it, just the same as it will with IR.)
Cheers,
b&
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