U of S | Mailing List Archive | alt-photo-process-l | Re: again on color absorption

Re: again on color absorption

Just to get it right in my mind, when you use the word "absorption", your saying the light goes through the negative and not reflected?

Yes, this is applied to a transparency (first two graphs, where the first shows the Pictorico absorbance)
I'm trying to get a better understanding of your graphs.
Looking at the middle one with all the 2400 inks, at the 370nm point, I can see that the green ink is the highest on the graph. Meaning that the light at 370nm when hitting the green ink will reflect most of the light.

It is an absorption measure, hence the green ink is absorbing most of the light @ 370 nm
Therefore the magenta which is the lowest on the graph for the 370nm will "absorb" most of that light and penetrate the surface of the emulsion?
Am I correct in saying this?

No, that is not correct. Magenta is the less absorbing, so that most of the light passes through the ink and goes to the emulsion (which darkens).
What sort of tools were used to do this sort of measurement?

For the first two graphs, a spectrophotometre. See the thread on this argument started about two or three weeks ago.
The third figure is a negative with H=0 to 360 on the x axis and S=0 to 100, B=100 (upper part) and B=100-0, S=100 on the y axis. The dashed lines help to find the pure colors (B=100, S=100).
see http://www.inkjetnegative.com/images/RNP/rnp.htm