I'm tired of having to wait for the perfect daylight outside and would like to have a small experimental setup to do some camera profiling and related experiments.
I want a full spectrum without spikes, and it seems like Solux 4700K lamps is the only thing out there, unless you get those new expensive multi-channel leds like gamma scientific RS-5B
http://www.gamma-sci.com/products/rs5b/.
However, the Solux seems to vary a bit so you need a precise dimmer with overdrive capacity, preferably up to 16 volt. If you don't worry about burning out the lamp soon it seems that you can get 5000K with very high similarity to a real D50 spectrum (without UV) with this lamp, but this is when running it in overdrive.
I would have preferred D65, but the only thing I've found there in terms of Halogen is Ushio Whitestar and I don't think their filtered lamp is without spikes (ie spectrum match with D65 is poor), but I'm not sure. Making a camera profile from D50 is okay though, that's actually what I've been using most of the time anyway.
I think I can do with one lamp only, there will be issues with uniformity for sure but a flatfield shot should solve that issue.
I'm currently looking for a fixture and a power source to be able to run that Solux 4700K lamp in say 8-16 volts with precise voltage control. I have a photospectrometer to measure the actual output.
I find it a bit surprising though that there are no LED solutions out there with good spectrums, except that gamma scientific. I've found this research project too with even more precision:
http://www.nist.gov/pml/div685/grp03/vision_lighting.cfm it feels like someone should have made a LED-based D65 lamp with 10 or so LEDs by now to make a full spectrum without spikes... I haven't found any though, Solux halogens seems still to be the king in (affordable and readily available) daylight simulation.
I am satisfied with fluorescent "daylight" lamps for print viewing, but when it comes to camera profiling I don't want a spiky spectrum.
Any tips, ideas, experience?