Re: Cyanotype/Cuprotype


Jim Patterson,
 

Hi All, 
I have several Cuprotypes several years old with no blue stains.
If any iron is left in the paper, a Cyanotype blue stain will result.  After developing in the thiocyanate/citric acid solution, wash well in at least 3 trays of citric acid water (1/2 tsp/liter) to remove all residual iron.  Then tone with the potassium Ferricyanide.  You can skip the Ferricyanide toner and use the Selenium/Sulfide toner at this point for a dark brown.

If printing a Cyanotype/Cuprotype combo, print the Cyanotype first to avoid changing the Cuprotype to a Cyanotype.

You can selectively change parts of a Cuprotype to a Cyanotype by using a small brush with Ferric Ammonium Sulfate solution.
Jim




On Jun 1, 2021, at 7:22 AM, Niranjan Patel via groups.io <nirpat89@...> wrote:

Hi, Bruce:

I am afraid a cuprotype is probably not in the cards for me imminently but when and if I try it, I will be sure to share here. 

Blue staining is probably something to do with not being able to clean out the residual irons, I am guessing but Jim would be the one to ask.

:Niranjan.

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