SORAA
did have 5000k and 4000k options before they discontinued them, and they were (are) fabulous. I've set up an entire viewing wall with both 5000k and 3000k soraa lamps, and they are performing extremely well. They are track mounted about 15 feet up to give about an 8 foot sweet spot on the wall, and evenly spaced to provide for maximum uniformity. The idea is that clients can see the difference the lighting color makes when going from D50 print standard to halogen equivalent-- in chromaluxe dye-sublimation especially things can shift quite dramatically (black and white shows considerable color inconstancy).
I can take some photos of the setup and post some spectral plots if anyone is interested-- this is installed as our main viewing wall at Griffin Editions.
Of course, I'm relying on bulbs which are no longer in production, but I've been able to work some magic with Soraa to hopefully maintain availability of the 5000k engines themselves.
I tested a large number of possible LED types, including the Yuji LED D50 strips and Ketra color tunable bulbs, but nothing could compare to the smoothness of the soraa spectrum, especially with regard to spectral power in the cyan range. They also have incredibly good R9 values, which can be difficult to attain. Anyway, proof is in the numbers, so if you guys are interested I'll post some pics.
I'm sure i'm going to have to deal with some color temperature drift, but for now this has been a fantastic asset for our particularly difficult setup (evenly lighting very large prints is HARD). The downside is now I go to many of the galleries that show work that we produce and there's some insane mixture of halogen and CFLs or what have you-- even in the very high end ones!
My dream is to one day set up a photo show that will cover everything from scan/digital file workflow through to lighting and display, but that day has not yet come...
One last note, in my conversations with GTI about their developing LED technology, the main concern they have is drift. I think the solution eventually will be to have some type of colorimeter built in which can re-tune the output of the various phosphors and take care of drift over time, but the industry is developing rapidly, and we are going to start seeing real options very soon
EDIT**
Attaching plots of the lighting for 5000K (ish) and 3000K Soraa bulbs-- should be pretty clear which ones are which
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