Display lighting for photographs

[Bruce Watson]

I'm looking to help a client. They have existing tracking lighting and fixtures. This limits us to PAR30 bulbs. They won't go the low voltage route, so MR-16s are out. So are fluorescents.

Within the small subset of lamps that PAR30 represents, I'd like to get as close to D50 as I can. I haven't been able to get very close however. The best I've found is a Sylvania Capsylite with a color temperature of just under 3000K, and a CRI of 100. Anyone know of a whiter lamp?

[Robert A. Zeichner]

Maybe a little gel? 1/8 booster blue, if I recall might do the trick. Go to www.rosco.com

[phil sweeney]

You could just use a standard bulb. Look at the GE "reveal" line. Different color temp. You will lose some brillance as a compared to the reflector PARs. The PAR 30 is 75w max. I believe you can use a standard bulb to 100w. Most housings list the maximum wattage.

[paulr]

aren't there a lot of 3200K bulbs? i thought this was the standard being used for most display lighting (not counting tungsten flood lamps, which are even warmer)

[Bruce Watson]

If there are a lot of 3200K bulbs, then I'm blind. So shoot me ;-) And there's some evidence that I might be going blind anyway - some out of focus areas on some recent sheets that I *know* I put my loupe on. Go figure.

Got any particular brand you'd like to share? The Sylvania Capsylite is still my leader at 3000K with a CRI of 100. I've actually got some that I use in track lighting and it does a good job - nice smooth pattern and nice fall off. But it's too darn yellow. Makes my B&W prints look muddy.

I thought by now there'd be better stuff on the market. But if there is, I can't find it. Hence my request for help.

[paulr]

i could be way off ... i just had the idea that 3200K was a halogen standard. maybe that's for the low voltage ones?

[Henry Ambrose]

Bruce,

The Capsylite is a lens and reflector design AKAIK, not necessarily a color temperature output. They do make them in a version to compete with the GE Reveal lamps that have a coating to bring the output up in temperature and improve the CRI. I don't know where you got the CRI of 100? Unless that measure has been altered, 100 would perfectly compatible with daylight and I'm pretty sure these lamps are not that. I think the number might be more like 80 - 85, but that is a lot better than regular lamps.

3200K is the "photo flood" standard, standard tungsten household lamps are more in the 2800-3000K range.

What about the flourescent spiral tube lamps for these kind of fixtures? I know you said flourescent was out for these folks but I think those lamps are made in a D50 version with a very high CRI and they would screw right in.
I'm wondering about why certain solutions are not acceptable. It could be that converting to low voltage but using the same tracks might be economically feasible if expense is the issue they're fighting.

Beyond just CRI numbers you might also look at spectral distribution graphs for the various choices. Some lamps, especially flourescents have big spikes of certain wavelengths and will be less desirable than smoother distribution.

[Bruce Watson]

I got the CRI specification from the manufacturer. (http://ecom.mysylvania.com/sylvaniab2c/b2c/z_login.do;jsessionid=ID4001DB0.12940018763105898End;sapj2ee_*=4001)
You have better information you'd like to share? Let's have it.

Can't use anything but a PAR30. That's why I asked about PAR30s. That's why I said "MR-16s are out. So are fluorescents." PAR30 is the parameter I have to work within. It's not a variable. I don't know how to make it any clearer. Sigh...

[Henry Ambrose]

OK Bruce,

I went back and read your original post and you certainly did specify what you were asking for and what would not be acceptable.

IME, CRI has been used with standard daylight at 100. If your PAR30s are "too yellow" then I'd say they must be using CRI in a different (perhaps relative to some reference other than daylight) manner.

You didn't seem to be getting anywhere so I tried to pitch in and asked a few questions to find more details about your requirements. Perhaps it was economic, or a sensitivity to flicker from flourescents that disqualified the other lamp possibilities. Something that could be overcome or worked around.

Now that I know your requirements twice over I suggest you ask the manufacturer, they'll most likely be open for business tomorrow morning. On the other hand, the Sylvania Capsylite PAR30 may be perfect for you, just wear light blue glasses while looking at your prints.

{half growling/half grinning}

[Bruce Watson]

Well, I think I'm just chasing my tail. I think I'm up against the limits of what a quartz halogen will do in a PAR30 configuration.

Now if only LEDs will get cheap enough. But they have their own problems...

Thanks to everyone for your help. And thanks to Henry for not swatting me, even if I deserve it sometimes. ;-)