[Alt-photo] Optical density

[Erich Camerling]

Measuring optical density at 380 nm. ( X-Rite 361T ) will give a lower
measured optical density value compared to 365 nm.
Because alt-photo processes using ammonium ferri-oxalate have their
maximum sensitivity from 313 - 365 nm.I measure at 365 nm.
(340 nm. is the optimum) but 340 nm. UV-LED's are extreme expensive
and many Epson inks have their optimum in the  365 nm.region.