On 2007 Sep 12, at 2:09 AM, Graeme Gill wrote: > There is a rather large disparity between the Graphic Arts > standard Illuminant D50, and the sort of lighting most people > use indoors. Even the higher quality 5000K Fluorescent lights > don't have a spectrum that much resembles D50, and the Ultra > Violet content of the lights is another wild card when combined > with Fluorescent Whitener Additive in paper stock, since the UV > output is often not closely controlled. You ain't kiddin'! A year or two ago, I ordered a handfull of compact fluorescent bulbs advertised as being 5000K with a CRI of 92. I plugged them into the living room, rather excited...and immediately thought...``Gee, they sure seem somehow hollow and excessively blue.'' So, I immediately broke out the i1...and, sure enough, they were a perfect match for one of the standard F illuminants whose spectrum is so bad that the G-M share tool couldn't even calculate a temperature for it -- let alone a CRI. Fortunately, the company I bought them from only gave me a minor hassle to return them. The only difference with most of the rest of the lights in my apartment is that they're reddish - yellowish - orangish instead of bluish...and they cost a fraction of what the ``CRI 92'' bulbs did. The kitchen, I've mentioned, has tubes that (according to G-M) really *do* have a CRI of about 92 (I forget exactly what). It's good enough for a ``rough guess'' sort of look at a print, but for real evaluation I step outside. > The closest practical lighting are filtered Quartz Halogen > lamps, such as Solux <http://www.solux.net/>, although I'm not > sure that the UV content is the same as real D50 daylight (in > fact they seem to boast that it has low UV output, making them > rather unsuitable for viewing substrates with FWA under standard > D50 conditions.) I've spent a lot of time over the years looking for affordable quality lighting. The Solux lights are tempting...but awfully expensive. I'm currently toying with getting some Lumiram Ecolume CF bulbs for ``normal'' lights (they claim 5000K and a CRI of 96), plus a pair of their 6500K CRI 98 tubes for the kitchen. They're cheap enough that I won't get too upset so long as the CRI is over 90. I figure they'll be much, much better than what I have now, even if they're not in the same league as a skylight. (The landlady might complain if I started cutting holes in the roof, as would my wallet....) If the tubes are as good as they claim, I'll probably even make a viewing booth from them, and maybe also a softbox. But that's probably just wishful thinking. Cheers, b& P.S. I took samples of the light in the gallery at the Tempe Library where my pictures will be shown in a couple months. I've got the .txt files to make .sp files, and G-M says they're a close match to a standard ``A'' illuminant. Good thing I took the samples.... b&