Sciencemadness Discussion Board

Seawater - reducing bleaching effect

CHRIS25 - 3-10-2012 at 04:51

Hi, strange as it may sound I experimented by placing cyanotype strips in seawater. I knew they would bleach slightly, actually I thought they would be destroyed; but too my delight I got consisitent reduction of the prussian blue to varying degrees resembling black and white photography, (the latter is quite complex to produce from a cyanotype requiring special chemical treatments). So as a result I would very much like to reduce the effects of the sodium and chlorides that are in seawater responsible for the bleaching. I know that seawater main salts are Cl 55% - Na 30% - SO4 8% then Mg and Ca following behind, (estimates I know). Sodium chlorine magnesium sulphur potassium and calcium make up the largest constituents, and my idea is to see if I can perhaps lessen the effects of the sodium and chlorine so as to allow the next few to dominate a bit. Is this a ridiculous tall order? It's all crazy experimentation, but the black and white is quite incredible. I have bleached cyanotypes with sodium carbonate and ammonia many times, this has always reduced the image before its toning bath but never the same as the seawater treatment. Anyway, just ideas I am having, suggestions are of course welcome. (Just in case some need to know Prussian blue is the potassium ferricyanide and ammonium iron3 citrate mixed).

ScienceSquirrel - 3-10-2012 at 06:23

Why not just buy magnesium sulphate ( Epsom Salts ) etc and use that.

CHRIS25 - 3-10-2012 at 06:52

Well, funny you said that I have loads of magnesium sulphate and I am definitely going to try that today, but in the meantime I wanted to post the question because seawater is a concoption of many ingredients, and I was thinking maybe someone might have an interesting insight or an idea that I would not think of, being that I am not a chemist with all that background. But thankyou mr.squirrel, for the suggestion.