Originally Posted by Vaughn
Part B is Potassium FERRIcyanide, not potassium cyanide. Potassium cyanide is a deadly poison and is used in the wetplate collodion process by some. Potassium ferricyanide is much less toxic and until recently, I had always read that it was rather benign. It is the bleaching component in sepia toner.
You don't want to heat or mix acid with either compound because deadly hydrogen cyanide gas will evolve.
As far as the mold problem, I simply filter the pt. A solution to remove the mold. I've heard thymol will also help prevent it. A couple drops of Listerine antiseptic mouthwash would probably do the trick...
Thanks Smieglitz, PE caught that gaffe of mine a few hours ago. From what I understand it takes a pretty strong acid to break down Potassium ferricyanide -- stronger than working solutions of stop bath and fixers.
I would use Listerine before using Formalin - formaldehyde. I think PE's suggestion of boiled water is a good one -- perhaps sterilizing the container and measuring devices also.
Thanks all for your input. I went to the farmacist yesterday and hoped I could buy some destilled water, but they only had sterilized water (which if I understand it is almost the same).
I will boil the glass bottles as well.
There seems to be some general confusion about the formulas, both the Classic and Cyanotype II can be found here:
Cyanotype II process:
And i also agree, don't keep any chemicals in the fridge! Especially not if you have kids, i know what my kids are like, getting into everything!
Coffee filter or cheesecloth should do the trick of straning any mould.
Yea a few drops of 100% thymol solution in a liter of Part A works great. I've been using it for years. Thymol also works well to perserve gum acacia mixtures if you mix from powdered gum.
Originally Posted by smieglitz
Unflavored Listerine could possibly work okay too.
Sponsored Ad. (Subscribers to APUG have the option to remove this ad.)
Well, you can't make a 100% thymol solution, as thymol is a solid at room temperature.
Originally Posted by donbga
I usually use 10% in alcohol, but listerine is just fine.
About 1 drop of the 10% / 100 ml of solution will be fine.
I have to ask you with listerine do you mean like a mouth-wash?
Originally Posted by brummelisa
Yes, sorry, in the US Listerine is a mouthwash that contains Thymol, Menthol and a few other ingredients that kill germs.
Thymol can be purchased from many chemical companies and druggists, and is pure enough to prevent contamination. Listerine has so many ingredients that contamination is possible.
Well Ron you can make a 100% solution or close to it. 50 grams thymol dissolved in 50 ml 70% isopropyl alcohol. This solution was offered to me by Sam Wang, so if it's good enough for him it's good enough for me.
Originally Posted by Photo Engineer
That is a 50% wt/vol solution. It is certainly ok, but very strong. It is by no means 100%.