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

Re: again on color absorption

Katharine, the only case I can remember that you have brought this issue
(gum tonal reversal, that is) into consideration was your 21-step tablet
test prints on glass - not HSL array... So nothing is refuted (as well as
nothing is proven) in my view -> since these two are completely irrelevant

12 Mayıs 2009, Salı, 5:34 pm tarihinde, Katharine Thayer yazmış:
> 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.
> Katharine
> 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...
>>> So,
>>> 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.
>> Alberto