OK John, I'll bite - 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? And if so, what type of lights produce the least UV? Hal On May 26, 2013, at 2:00 AM, John Castronovo <jc@technicalphoto.com> wrote:

Does it help? The right place for filtering u.v. is at the light source. Once the artwork is fluorescing from u.v. light you can't filter the problem out at the camera. More IR filtration at the camera can help with some art, especially if you're using hot lights on a subject having colorants prone to metameric failure but it's still better to use lights that emit less IR in the first place.

-----Original Message----- From: Millers' Photography L.L.C. Sent: Sunday, May 26, 2013 12:55 AM To: colorsync-users@lists.apple.com List Subject: B+W 77mm UV/IR Cut (486M) MRC Filter

I must thank someone on this list that suggested purchasing the B+W 77mm UV/IR Cut (486M) MRC Filter for issues I had with reproducing a particular piece of original art. It was around June 15, 2012. I purchased a B+W 67mm UV/IR Cut (486M) MRC Filter as well. These filters are always on the shooting lens.

I don't remember who it was. I have been asked who it was. If you are out there, please respond.

Warm Regards,

David

David B Miller, Pharm. D. member Millers' Photography L.L.C. dba Spinnaker Photo Imaging Center Bellingham, WA www.spinnakerphotoimagingcenter.com 360 739 2826

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One needs an IR filter if a beam from IR remote control makes a purple spot on the shot, or if a black plastic or wool turns purplish. Digital sensors have very low UV sensitivity. On May 26, 2013, at 10:57 AM, John Castronovo wrote:

I don't really know what's best to be honest. Some of the new LED units are looking pretty good while many continue to use HID and full spectrum fluorescents. For hot lights, Solux lamps are supposed to be very well filtered at both ends of the spectrum but you'd need a lot of them to light a large piece of art. Plastic sheeting used to filter U.V. is available cheaply in large rolls so it's easy to use it over any light source, but good IR filtration isn't so I use Schott glass IR filters behind the camera lens. I think LED and wide spectrum fluorescent are much better choices than quartz when it comes to IR, but as in the case with Solux which is internally filtered, each lamp is different so it's hard to generalize without comparing the manufacturer's data.

-----Original Message----- From: Hal Hinderliter Sent: Sunday, May 26, 2013 10:25 AM To: John Castronovo Cc: Millers' Photography L.L.C. ; colorsync-users@lists.apple.com Subject: Re: B+W 77mm UV/IR Cut (486M) MRC Filter

OK John, I'll bite - 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? And if so, what type of lights produce the least UV?

Hal

On May 26, 2013, at 2:00 AM, John Castronovo <jc@technicalphoto.com> wrote:

...

Does it help? The right place for filtering u.v. is at the light source. Once the artwork is fluorescing from u.v. light you can't filter the problem out at the camera. More IR filtration at the camera can help with some art, especially if you're using hot lights on a subject having colorants prone to metameric failure but it's still better to use lights that emit less IR in the first place.

-----Original Message----- From: Millers' Photography L.L.C. Sent: Sunday, May 26, 2013 12:55 AM To: colorsync-users@lists.apple.com List Subject: B+W 77mm UV/IR Cut (486M) MRC Filter

I must thank someone on this list that suggested purchasing the B+W 77mm UV/IR Cut (486M) MRC Filter for issues I had with reproducing a particular piece of original art. It was around June 15, 2012. I purchased a B+W 67mm UV/IR Cut (486M) MRC Filter as well. These filters are always on the shooting lens.

I don't remember who it was. I have been asked who it was. If you are out there, please respond.

Warm Regards,

David

David B Miller, Pharm. D. member Millers' Photography L.L.C. dba Spinnaker Photo Imaging Center Bellingham, WA www.spinnakerphotoimagingcenter.com 360 739 2826

_______________________________________________ Do not post admin requests to the list. They will be ignored. Colorsync-users mailing list (Colorsync-users@lists.apple.com) Help/Unsubscribe/Update your Subscription: https://lists.apple.com/mailman/options/colorsync-users/jc%40technicalphoto....

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-- Best regards, Iliah Borg

On May 26, 2013, at 7:25 AM, Hal Hinderliter <hal@halhinderliter.com> wrote:

which type of studio lighting emits the least IR?

On the separate question of lighting recommendations, I personally can't recommend Paul C. Buff Einsteins highly enough. I get great results with them; there's nothing I wish of them that they don't provide; they're very affordable; and PCB customer service is unbelievable -- everything you ever wished of a company and more. I'm sure there're better lights out there in an absolute sense, but they're not going to be significantly better...and they'll be a hell of a lot more expensive. For those on an especially tight budget, PCB AlienBees are the only lights to consider. They lack in features, not quality, and one can work around the lack of features. If whatever you're doing is so critical that you can't, then you can afford the Einsteins instead. Cheers, b&

On May 26, 2013, at 10:23 AM, Robin Myers <robin@rmimaging.com> wrote:

UV light should always be filtered out at the source not just to control fluorescence, but more importantly to eliminate damage to the subject. UV is high energy light that breaks molecular bonds, altering the artwork. It can easily fade more fugitive colors, degrade optical brighteners, can cause chemical changes, and much more.

Without disputing any of that, outside perhaps of very rare instances in preservation of very fragile objects, I don't see it being a practical concern in reproduction work. If the work is carried uncovered from the parking lot, it's going to get more UV exposure than in the imaging process. Unless a minute or two of direct exposure to the Sun is going to damage the work, nothing you'll reasonably do to it in the studio will, either. (Of course, there are unreasonable and even stupid things you could do in the studio, like set a hot lamp inches away from the art and leave it on while you go to lunch....) Where the UV content of the light becomes a concern for damaging art is in display conditions. If there's nothing fluorescent in the art, you don't want any UV light on it to prevent just the type of damage you describe. But, if there *are* fluorescent pigments in the art, and especially if the fluorescent pigments are a prominent feature of the art...well, you'll want to display the art under light with plenty of UV in it in order to best showcase it, but you'll also want to consider ways of limiting the exposure. For example, you could significantly dim the ambient conditions and use a directional UV-rich source to illuminate the art (which won't have to be as absolutely bright), and you can only turn on the UV-rich light when the work is actively being viewed. But you also have to acknowledge that the work has a limited lifespan, no matter what you do, and that all you can do is prolong its life.

There are also big issues with flash units in their exposure and color variability. It is more by luck than design that some may be acceptable for fine art imaging, most are not, and I do not recommend their use.

That's one reason why I recommend the Einsteins. Their color and output constancy was *exactly* the driving factor in their design. They offer two modes: a ``constant color'' mode and an ``action'' mode. In constant color mode, the color temperature is held constant at 5600K +/- 50K over the entire power range. Even in action mode, the color temperature only varies from 5600K to 6300K over the range. And, in practice, I can't spot any deficiencies in their operation. Not only are they extremely stable, they're extremely consistent between units (no more than 1/10 stop variation, and that may well be due to light placement / aiming). They're also very linear; if I set up the lights in a copy stand configuration and adjust them all by 1/10 stop, the resulting exposure changes by 1/10 stop. Cheers, b&

On May 26, 2013, at 2:14 PM, José Ángel Bueno García <jbueno61@gmail.com> wrote:

But if you measure your working area with your photometer/flash meter with 1/10 stop accuracy and test with Imatest you will note that isn't enought accuracy.

1/10 stop works out to about 2 DE in the midtones, roughly. Significant, yes, but only barely. The thing is, even the best lenses have much more than 1/10 stop differential across the frame. 1/10 stop is more than plenty for the capture phase of things. You'll of course, no matter what, want to take a picture of a white field in the exact same setup and use that to take care of any and all residual unevenness in illumination. But trying to get your lighting more even than even a third of a stop is probably a waste of time, as even that's better than your lens. If it's inter-shot repeatability you're worried about, my experience with the Einsteins is that, shot-to-shot, there's less than 1/100 stop variability. No human is going to be able to spot the difference...but, if you're still worried, you can take multiple exposures and blend them in a stack in Photoshop with the blend mode set to median. It'll reduce noise, too...not that noise is a factor with proper exposures on modern cameras in studio settings. But it'll also protect you against one of the units not getting the signal to fire, which does happen every few hundred shots or so (depending on how noisy your RF environment is). Still, considering how cheap it is to fire off a few shots instead of a single one, it's good insurance. Cheers, b&

On May 26, 2013, at 3:47 PM, José Ángel Bueno García <jbueno61@gmail.com> wrote:

I'm sure that my old Minolta IV with its accuracy of 1/10 will stay with me for years, but what kind of instrument you make use of to obtain 1/100?

I'm getting those numbers by shooting a chart, developing it as a linear 1.0 gamma UNIWB TIFF, building a profile from that, doing a reverse lookup of L*=100 a*=0 b*=0, and comparing the resulting RGB values across multiple frames. This is all wrapped up in a Perl script, of course. It generates numbers (in EV units, or stops) that I then feed to Raw Photo Processor to simultaneously normalize exposure and set white balance. This is typical: _06C3301: R = 1.20476442084827 G = 0.112331028392598 B = 0.72696339739706 _06C3302: R = 1.20242543114168 G = 0.109944528198645 B = 0.722810030669048 _06C3303: R = 1.20551595895193 G = 0.111145831718312 B = 0.723527251434194 I think most will agree that a difference of 0.003 EV is entirely academic -- at least, in this context....

And what about 2dE asociated to a difference of 1/10 stop?.

Open an image in Adobe Camera Raw (or the like). Find something neutral -- use it as the white balance reference if need be. Adjust the exposure slider until it's a midtone. Now, change the exposure slider by 1/10 stop. You'll see a difference of about 4 RGB units, which works out to about 2 L* units (check with the color picker) -- or, roughly, 2 DE. You could calculate it more precisely, I'm sure, but we're discussing rough approximations in the first place. Cheers, b&