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Old 11th June 2018, 12:39 PM
alexmuir alexmuir is offline
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Default Gum Bichromate

I tried this at the weekend, but now have some questions!
Is there a risk of inhalation of toxic fumes from the Dichromate solution? I was only using 1-2ml of a 10% solution at any time. I wasn’t aware of any strong smell.
I initially planned on shrinking and sizing paper, but was told that Bergger Cot 320 didn’t require that. What I need to know is which side to coat, rough or smooth?
I made some prints which I washed for 20 mins, then dried. Is it safe to handle them, or is there still a toxic risk from the Dichromate?
Thanks for any advice,
Alex.



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Old 11th June 2018, 02:08 PM
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Alex, in The book of alternative photographic processes 2nd ed. 2009, Christopher James comments on the hazards of using ammonium or potassium dichromate, as follows:


"Note: Be cautious on how you handle ammonium or potassium dichromate: It is dangerous and poisonous and highly allergenic. Never put bare skin in contact with any dichromate solution. This chemical can cause lesions on your tender flesh and can damage your lungs by breathing it in its dry state. Be very careful with storage...".


He seems not to comment on which side to coat: it may be a matter of preference. [Spirits of salts doesn't comment on that either]


James's book has a 36-page chapter on the process. Might the Art College library have a copy you could borrow or consult? If not, give me a shout and I can do some photographing for you. amazon.co.uk have the 2015 3rd ed. for sale but it's £66.99.

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Old 11th June 2018, 02:37 PM
alexmuir alexmuir is offline
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Thanks, Michael. That is helpful. The book I have suggests consulting the MSDS for the product, but I’ve no idea who produced my sample of Potassium Dichromate. I bought it via eBay.
The paper has a smooth side, and a very slightly textured side. Perhaps both can be used.
I will try the Art School library. I hadn’t thought of that.
I am wondering whether a safer, less toxic process may be the way forward. I’ve seen many good examples of Cyanotypes, including your own, and salt prints, etc. There is certainly a range to choose from without need of toxic chemistry.
Alex


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Old 11th June 2018, 04:30 PM
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this may help with the safety issues
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Old 12th June 2018, 10:45 AM
alexmuir alexmuir is offline
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Quote:
Originally Posted by Ian Marsh View Post
this may help with the safety issues


Thanks, Ian. I can’t seem to open the document. I will try it on a PC later today.
Alex


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Old 12th June 2018, 12:56 PM
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This may be better
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Old 12th June 2018, 01:33 PM
alexmuir alexmuir is offline
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Thanks, Ian!
That makes it very clear. I have the chemistry for Cyanotypes, Argentotypes and a couple of other processes I can try without a serious health risk. I think I was taken in by the work of the Pictorialists of the late 19th and early 20th Centuries. I'm sure good prints can be obtained, however without Potassium Dichromate.
Alex.


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Old 12th June 2018, 02:12 PM
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The book that I copied that from would be a useful addition to anybody using photo chemicals, especially alternative processes. it gives good safety advice and lists all the chemicals you would ever use.

http://www.conservation-resources.co...191574fee0bac5
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