As you pointed it, I've been reading that.
http://heilandelectronic.de/files/do...t_Brochure.pdf
It is a good product, well finished, and straight, a good option. It cannot be cheap... Still diffusion only is available.
I'm asking myself how CRI (color reproduction index) of the light source may impact fidelity in color work. I bought a box of 8x10 Fuji CDU II transparency copy film and I plan to copy Velvia/Provia transparencies, and enlarging MF slides to 8x10 slides, perhaps this can be known by making contact copies of an IT8 slide target, under different light sources...
For what's WB I think that if blue channel is able of rendering grade 5 and green channel can deliver grade 00, I think that it has to work well. A problem would be a too greenish blue channel or a too bluish green channel , then perhaps only 1 to 4 grades would be available.
One interesting thing to test it would be the VC paper spectral response... it may depend on the aniline used for green sensitization. Perhaps it can be done by testing different green LEDs, of some 30nm difference in their emision peaks...
From ilford information
http://www.ilfordphoto.com/Webfiles/...0201152306.pdf I undertand that there are 3 emulsions, 1) with no green sensitization added, 2) with some green sensitization added, 3) with a lot of green sensitization added.
I understand (guessing) that 2) and 3) emulsions have the same specific green sensitization dye, but in different ammounts. They could use a different sensitization dye (green-bluish) for emulsion 2), but I guess that would give more inconsistent results under different light sources. If it is like this, it simplifies a lot light source for VC paper, I think. (also knowing cold cathode issues with VC...)
In my DIY LF enlarger I don't want to give up the possibility of condenser type, not of the filament type, but of the bulb type. I plan to use the Fujimoto concept, that can switch from condenser to diffuser. I think that the today's solar energy fresnels and powerful LEDs availability changes design rules...
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