RE: Potassium dichromate

[Liam Lawless <lawless@ic24.net>]

You'll find some of the info you're looking for on p.69 of The Keepers of
Light.  If you don't have it, I can scan for you, but not until after
Tuesday of next week.



Liam

-----Original Message-----
From: lva [mailto:lva@pamho.net]
Sent: 31 July 2001 18:00
To: alt-photo-process-l@sask.usask.ca
Subject: Potassium dichromate


Hello chemists!

I'd have a couple of questions about the dichromate. Anyone out there
who's got answers?


What is potassium dichromate?

How is it produced?

Was it known as a chemical compound prior to the 1830s?

In some books it is also called dichromate of potash. What is potash and
how is that produced?

Is the dichromate itself light sensitive?

And how did these people in the 1830s figure out that dichromate hardens
gum arabic when exposed to UV light? Did they intend to harden gum
arabic and simply try out thousands of chemicals?


Whatever I have read so far about the gum dichromate process does not
seem to address these points.

Greetings from Sweden

Brahma