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

Re: again on color absorption

Ah, that makes more sense than the explanation for a one-time only appearance of this phenomenom in gum (on an HSL array) which was advanced on the hybridphoto site, and which has been advanced on this list from time to time, that the tonal inversion is a function of underexposure, or because the "negative" had too long a density range for the process. Both those explanations were easily refuted; this one has some merit in your case, especially if it happens every time. Mine, as I said, happened only once in many printings of the same HSL array with the same light source and correct exposure time, so this explanation wouldn't work for what happened in my case any better than the other ones did.


On May 12, 2009, at 2:09 AM, Alberto Novo wrote:

Katharine, IIRC, the portion below the dashed line (pure color) would be
less colored ink(s) + more black ink (due to less lightness/ brightness -
depending which test pattern is used) as you progress more to bottom.

Now I am undestanding...

my understanding of Alberto's test would be that black ink isn't as opaque
to the specific light which that specific process requires as some other
colored inks, that's why there's reintroduction of tone. This is something
I experienced with Epson 890/1290 OEM dye-based inks and HP9180
pigment-based inks.

You are right, the mixing of colour with black decreases the amount of both. The absorption of pure black is in the last row, which is a little denser (absorbing less) than pure green.