U of S | Mailing List Archive | alt-photo-process-l | Re: I stand corrected

Re: I stand corrected

And to answer your question, there is no doubt you can get extremely dense negatives from combining colors. For instance, a 60% yellow and 60% cyan mix yield predicted densities of 2.4 and .92 individually on my 7800. Combining the two into a green color will get you a predicted density of 3.32. This is very close to what I actually see. The only joker in the deck here is the total ink percentage. You can see that the above example loads a120% ink load onto the film. This is dangerously large. I like to keep the total ink % in the 60-90% range. Which means that lower percentages of denser inks is the way to go.
On Apr 13, 2009, at 6:30 AM, Loris Medici wrote:

I inspected the UV transmission density charts Clay kindly shared, and I
have to correct myself:

Whereas yellow is the densest of all inks - which was one of my points,
this doesn't necessarily mean that it's even denser than combination
colors (such as Y+C -> Green). This is proven by the fact that with Epson
2400 yellow ink gives log 2.47 UV density by itself (according to Clay's
datasheet) whereas I'm pretty sure there are persons using this printer
for processes that require more DR than log 2.47. That proves my second
point (about printer ink limits and yellow being denser than green) wrong!
(So many CDRP tests with so many different processes - especially low ER
processes such as Cyanotype and Gum - got me confused; sorry for the