Re: Dates and names in history

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From: Sil Horwitz (silh@earthlink.net)
Date: 02/14/00-12:00:57 AM Z

At 2000/02/14 12:35 AM -0500, Judi wrote:

>On Sun, 13 Feb 2000, Campos & Davis Photos wrote:
> > Also can someone give me a real definition of what a dichromate is? I
> > know how to use them but from what substance do they originate?
>
>They're made from chrome.

Come on, Judy, you can do better than that. Sodium dichromate is made by
roasting chromium ore with lye (sodium hydroxide). The potassium dichromate
can be made the same way, but potassium hydroxide is much more expensive,
so the pot dichromate of commerce is usually made by a reaction between
potassium chloride and sodium dichromate.

Sil Horwitz, FPSA
Technical Editor, PSA Journal
teched@psa-photo.org
silh@earthlink.net
Visit http://www.psa-photo.org/
Personal page: http://home.earthlink.net/~silh/

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