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

Re: I stand corrected

The various densities seem to be roughly additive. You will notice that the graphs for each ink and ink percentage are pretty much linear. An equation for each color can be described with a simple a + bx relationship where b is the slope and x is the given percentage. Plug the percentage of each ink and find the predicted density for each color. Add them all up and you will get a value very close to what is actually seen. This is easy enough to prove for yourself using quadtone RIP since you have direct control over each ink percentage. It's not perfect, but pretty darn close.

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