Let there be full-spectrum, above 91CRI light
January 14, 2010 10:10 AM   Subscribe

Natural-light filter: Looking for a fluorescent bulb (T9) that will provide me accurate, daylight-like light for my art projects. Advice for other alternatives is welcome too!

I've got this desk lamp and I use it for art projects.

The main problem I have is getting natural lighting from it. I recently picked up the Color-Aid system and they suggest that "[f]or accurate color determination, use a full spectrum fluorescent lamp with a Color Temperature between 5000°, and 6500° Kelvin and a Color rendering Index (CRI) of 91 or above."

Problem is, I have googled high and low for a T9, 22w, fluorescent bulb that fits these criteria and haven't found squat.

I am wondering:
1) Does such a T9 bulb exist?

2) Should I just get a different lamp that might produce better results (keep in mind that I really like the articulating arm of this lamp and I'd prefer not to drop more cash to replace a relatively new lamp)

3) Since the lamp uses both incandescent and fluorescent bulbs, is there a mix that would produce the desired results? (I'm currently using one of those 120W "full spectrum" bulbs for the incandescent part of the lamp, but it still looks yellow-ish to me and the 22 Watt T9 bulb I have in there is far too "cold" to produce true-colors).

4) Will another bulb type fit (i.e. is there a circular fluorescent bulb that is not a T9 but will still fit in a T9 socket of this lamp?) that does have these amazing natural light properties?

Anyway, any suggestions surrounding this are appreciated!
posted by alrightokay to Media & Arts (6 answers total) 1 user marked this as a favorite
Believe it or not, I've bought those bulbs from Lowes.
I've bought them both in incandescent and halogen, though the halogens were very expensive.

Just ask for daylight balanced bulbs and you'll find them.
posted by damiano99 at 10:13 AM on January 14, 2010

I would look at photography places, especially someplace like B&H.
posted by sanka at 10:16 AM on January 14, 2010

Best answer: Damiano, the OP is looking for a fluorescent bulb.

...use a full spectrum fluorescent lamp with a Color Temperature between 5000°, and 6500° Kelvin and a Color rendering Index (CRI) of 91 or above

Forget about the "Full spectrum" and color temperature parts of that recommendation, and focus on the CRI. "Full Spectrum" is just another way of saying "high CRI." Also, all currently available fluorescent bulbs I've seen with CRIs of 91 or above have been in the color temp range you're looking for.

I can't vouch for this company, but it looks like there's one on this page.
posted by jon1270 at 10:30 AM on January 14, 2010

Yeah they just have them at Lowes or Home Depot.

Think about whether you want "full spectrum" or "daylight." Sunlight is yellowish. By comparison "full spectrum" will seem bluish.
posted by cmoj at 10:41 AM on January 14, 2010

Sorry, but there's really no such thing, despite the advertising claims, publishedspecs and the CRI and such. Fluorescent tubes, all of them, are discontinuous sources - they have peaks and valleys in their spectrum, and really can't approximate "nautral daylight" very closely, though somne do a better job than others. The advertised CRI ius supposed to be but isn't always, a good measure of that.

On top of this, the "natural daylight" outdoors is always different, minute to minute, day to day and place to place, though there are theoretical standards. Standard daylight (5600 degrees Kelvin) is a continuous spectrum standard, and can be approximnated by using a tungsten (incandescent or halogen) and filtering out some of the red end with filters. See the Rosco and Lee companies for cinematogrqaphiuc and photographic gels. But that can be hot, wasteful of energy and the filters fade over time. Xenon light sources (like that in a camera flash, only on all the time) can produce a nice "daylight spectrum," but they are vastly expensive.

If you are producing art works to be seen in a gallery, your best bet might be to use the same kinds of light sources to light your work space as will be used in the gallery. Many galleries use incandescent (around 2800 degrees Kelvin) or tungsten halogen (3000 to 3200 K) lighting.
posted by tommyD at 10:51 AM on January 14, 2010

Jon, you're right. I was reading too fast. My bad.
posted by damiano99 at 11:05 AM on January 14, 2010

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