4×5 8×10 35mm black & white C41 carbon transfer color color carbon color developer color negative crossover darkroom equipment DAS dichromate digital digital negatives dispersion double transfer ECN2 enlarger light source Epson 4990 film development final support Fomapan 200 glop inkjet Kodak Vision3 large format linearization paper pigment printing Pyrocat HD RA4 RC paper RGB LEDs scanning sizing subbing temporary support tissue tonal threshold UV exposure unit UV LEDs UV light source