By the effect of light, ferricyanide reduces to ferrocyanide which reacts with ferric ions from ferric ammonium citrate to produce a beautiful, deep blue color known as Prussian blue. However, cupric ferrocyanide has a nice wine red color and I would like to know if by changing ferric ions by cupric nitrate or sulfate solution, the photoreaction still occurs and produces red images instead of blue ones.
Thank you Mr. Hamada
What I want to know is if someone used it before to create a piece of art. My actual doubt is if cyanotypes using copper ions can last for years as those made using ferric ions. Of course the reaction can be easily done in a test tube...
Hi Major,
Do you mean substitute ferric ammonium citrate by cúprica nitrate?
cupric nitrate / cupric sulfate + potassium ferricyanide?
I’ve never done it before but I am already looking forward to testing it!
Daniela Remião de Macedo
Hi, I already tried this reaction and it actually did work, chemically speaking: a nice wine red color appeared after exposure to the sun, not as intense as the blue color generated by the ferric ferrocyanide reaction, but enough to get a few interesting images. However I still consider it just a chemical test on a sheet of paper. My concern has to do with the possibility of some talented artist creating a great piece of art using this reaction and after a few days, weeks or months it just fades away; in this case that would be such a shame...
Best regards ad thanks for asking.
Maynor Alberto
I am an artist, not a chemist, and I have been working with cyanotype for some years. So I would like to make sure about your suggestion in the formula. My doubt is actually which of the chemicals you suggest replacing with cupric nitrate/sulfate, is it the ferric ammounium citrate?
Hello
I replaced ferric ammonium citrate by cupric nitrate, but cupric sulfate might be easier Andrés cheaper to get in the market. However, cupric nitrate is much more soluble in water than cupric sulfate, so higher concentrations can be prepared. Of course, exact quatities should be tested and validated again.
Moreover, it is also possible to mix cupric nitrate and ferric ammonium citrate in order to get some purple tones. If you try, please let me know how it worked.
By the way, I haven't found any combination with ferricyanide to produce a strong yellow color. Barium ferrocyanide has just a very soft creamy yellow color so it doesn't work fine here.
Muito obrigado pelo seu interesse em saber mais sobre isto.
Best regards.
Cool! I will look for chemicals and test new formulas. Then I show you the results. Thank you very much for sharing the information! And thanks for the kindness of expressing yourself in Portuguese.
Best regards
I’m an artist phd intersted in getting started with cyanotype, is the problem with the red Cu substitute that it is loosely attached to the paper/textile etc., or that it is light sensitive? Perhaps a fixative could be applied, or a uv -filtering layer of some kind?
- Badges
- Science topic