I have been using Philips 930 T8 florescent tubes for lighting in my digital darkroom. I selected these lights because they have a 97% CRI and I have heard they are the exact same bulb as the ott-light uses. I have noticed that it has a distinct green cast which is totally useless in refrencing the prints from my Epson 9600 Ultrachrome. I have now added a second light fixture and put Sylvina Design 50 T12 tubes in it. They seems to have a redder/magenta cast to them which actually seems very close to daylight. If something looks good under the Design 50 lights it still looks good outside or under Tungsten lighting. I also have a Gepe Slide viewer that claims to be 5000k daylight and it has a similar cast to the Design 50 tubes. I have been reading about D50 lighting vs 5000k. It sounds like 5000k can be inconsistant between manufactures but D50 is an imaging standard. I have been looking at getting Halogen MR16 4700k lights by Solux. They claim to be D50 and highly regarded as the best D50 bulb. Does anyone have experience with these bulbs and the epson Ultrachrome 7600/9600? I don't want to order a bunch and put tracklighting in my work area if I don't have to.