Re: Sizing paper with gum and dichromate

On Dec 20, 2005, at 10:03 AM, Katharine Thayer wrote:

> . Since, as I reported here a couple of months ago, there's evidence
> that gum responds at wavelengths shifted considerably toward green
> from albumen's sensibility spectrum

Correction: this should read "dichromated gum" and "dichromated
albumen." As I recall the report, dichromated albumen and dichromated
gelatin have about the same sensitivity spectrum as dichromate alone,
giving people to assume that this is true with all colloids. But in the
one study that I'm aware of where someone actually looked at the
sensitivity spectrum of dichromated gum, they found that it was shifted
more into the visible spectrum, compared to dichromated albumen, and
that the difference was due to the difference in spectral profiles of
the two colloids.
kt
Received on Tue Dec 20 12:27:10 2005