U of S | Mailing List Archive | alt-photo-process-l | Re: Epson R2400 inks density

Re: Epson R2400 inks density

Alberto Novo schreef:
UV-A region is from 320 - 380 nm.
It depends on the bibliography. Someone else extends this range up to 400 nm, but I think this is not so important for our photographic purposes.
The minimum absorption of the yellow ink is at about 340 nm (not 440 nm),M and C have their maximum at 320 nm (not 420 nm) in the UV-A region.
You are right, that was I was thinking while my hand was digiting (an example of Jekill-Hyde effect?). I would not trust so much what is happening at wavelengths lower than about 330 nm, because of the strong absorption also from Pictorico. For me, there is too much noise (I0 too low) for a good representativeness of the data.
it is not useful to look at the curves above 380 nm. for Pt or Pd.
The spectra are useful in the frame of the recent discussion about the opacity of the different hues.
For silverprinters it would be very interesting if you could complete the data with the curve of Pyro stain.(stepwedge with and without Pyro)
I do not develop with pyro. Anybody would provide me a sample of pyro step wedge? If so, and if my friend is so kind do make an extra effort, I could give you a reply. Otherwise, try to give it to another chemist working with a specrophotometre.
So the M and C inks are the best blockers in this case at 350 nm.
G and C, not M and C.

Dear Alberto,
For people like me who only have Y,C,M,R,B and K inks best blockers are M and C, but you are absolute right when you have also G ink.