Be careful....if the solution contains Sodium or Potassium hydroxide (1 to 10%) you can get problems, if the bottle is made of PET see "Polyethylene Terephthalate (PET)--Chemical Compatibility"...
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Be careful....if the solution contains Sodium or Potassium hydroxide (1 to 10%) you can get problems, if the bottle is made of PET see "Polyethylene Terephthalate (PET)--Chemical Compatibility"...
Protectan would be a other option..according to the MSDS https://www.digitaltruth.com/products/tetenal_msds/protectan-MSDS.pdf itīs a mixture of butane, propane and isobutane.
Other sources (Flickr)...
Short update: It seems that citric acid is not working as reducing agent see my quick shot at
Minimizing wash water containing dichromate?
Bj68
Yes, that should work, too, but you have to extend the reaction time, because the concentration of the Cr(VI) is very low or you use more ascorbic acid.
I made a test with a big amount of water (10...
Well. thatīs the little problem what I have seen...
I tried this (precipitating) in a few different ways, but with no success:
a) adding sodium carbonate powder
b) adding sodium hydroxide...
It should work with citric acid, too
See:
[...]Other work by Hasan and Rocek (1973b) demonstrated that in addition to 2-hydroxy-2-methylbutyric acid, this reaction occurs with other α-hydroxy...
I posted this text at the altphotolist, too
Even if the amounts of dichromate are very tiny, there is a problem with the dichromate waste which is accumulated during gum printing.
In the...
I am in Zürich
Next processes will be Chemigrams and Silvergum
http://www.alternativephotography.com/wp/processes/gelatin-silver/silvergum-gum-over-silver-gelatin...
Dear community,
I am interested in gum printing and other alternative processes.
My personal info:
I have a light chemistry background (abandoned study) but I am more practical. Thatīs the...