U of S | Mailing List Archive | alt-photo-process-l | Re: ultramarine blue

Re: ultramarine blue



...If ultramarine is sodium aluminum sulfosilicate, is it possible, chemists on the list, that the acidity of the gum would be responsible for releasing this smell? I do have a hyper sensitive nose, I have been told.
In principle, yes. Our nose is very sensible to sulphidric acid (H2S), so it is enough that only a minimum amount be released.
I have never used ultramarine blue for gum, but I have prepared a lot of resinotype powder. This is made heatingh toegether rosin and pigment up to about 100-120C. Rosin is about 90% abietic acid, and a little sulphide smell is noticeable also in this case.
Alberto

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