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 cases. 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
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