Re: Gum problem(s)

From: MARTINM ^lt;>
Date: 11/20/05-12:31:44 AM Z
Message-id: <007101c5ed9c$3ce663a0$f6994854@MUMBOSATO>

----- Original Message -----
From: "Sandy King" <>
To: <>
Sent: Saturday, November 19, 2005 3:35 PM
Subject: Re: Gum problem(s)

> Dichromated colloid processes, including carbon and gum, have a
> maximum peak in the near UV at about 360 nm to 370 nm, varying
> slightly with pH and type of dichromate. From the peak at 360-370 nm,
> sensitivity falls off sharply to about 320 nm, at which point it
> starts to rise to another, and much large, peak at around 200 nm,
> where it has its maximum sensitivity. The peak at 200 nnm is really
> huge compared to the one at 360-70 nm, like Mt. Everest to the
> highest peaks in the Appalachians. On the other side sensitivity
> falls off very gradually in the violet and blue to near zero at
> around 520 nm.

I don't think that's entirely accurate for dichromated colloid systems. I
guess the data you quote, apply to the absorption spectra of a dichromated
water solution.
When it comes to dichromated colloids, sensitivity peaks might be
considerably shifted towards longer wavelengths. By the way, speaking of DCG
holography (dichromated gelatin), there are lots of people to expose their
DCG layer at 532nm...

Received on Sun Nov 20 00:32:48 2005

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