[Alt-photo] Cuprotype, Cyanotype-Toning Trials
jimbobnola at cox.net
Thu Sep 27 12:37:44 UTC 2018
If you are using Part A (copper sulfate) and Part B (ferric ammonium citrate, green) you can make each 24%. When combined 1 part A + 1 part B, you get 12% copper sulfate and 12% FAC in the coating solution.
To tone a cuprotype black, you can soak briefly in a combo of old developers, wash and it will oxidize to a fairly permanent black pigment as it dries. The old developers are pretty toxic though.
Also, you can get an excellent sepia by toning the print with selenium-sulfide toner, or sodium sulfide toner after the developer. In this case the ferricyanide toner is not used. Tone outside or in a fume hood as these toners are not nice either. I use the selenium-sulfide toner of Judy Segel, in Anchell’s darkroom cookbook.
Sent from my iPhone
> On Sep 27, 2018, at 7:17 AM, Jim Patterson via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org> wrote:
> Hi, the Cuprotype coating solution has high surface tension. Adding a drop or two of 10% Tween 20 or dilute Photoflo helps a lot in coating the paper.
> Jim Patterson
> Sent from my iPhone
>> On Sep 27, 2018, at 1:44 AM, BJ68 via Alt-photo-process-list <alt-photo-process-list at lists.altphotolist.org> wrote:
>> Dear List,
>> here are a few results of home experimenting:
>> First I tried the Cuprotype Process by Jim Patterson:
>> Yesterday I played a little bit with cyanotypes and the formula:
>> Tried to tone a exposed cyanotype (Exp. 11 and 5 min) with a bath made out of copper(II)sulfate and ammonium citrate. Reason for that, was this patent https://patents.google.com/patent/US2093421A/en
>> where I read this: [...]Upon exposure a piece of blueprint paper (a) becomes more and more blue and then (b) fades out to a light blue grey (c) becoming greyish White when Over-exposed. During (a) the ferricyanide is being reduced to ferrocyanide for a piece of paper at this stage when washed in an ammonium citrate-copper sulfate solution (from which ferricyanide will not precipitate copper ferricyanide but ferrocyanide will precipitate red copper ferrocyanide) gives a red print. [...]
>> I got (at picture not visible) light reddish tones and the blues turned to more blackish color, perhaps I had to adjust the concentration of the copper(II)sulfate higher....
>> The other trial was playing with the formula itself:
>> In short: To 5 ml potassium ferricyanide and 5 ml ammonium iron(III)citrate solution I put 10 ml of a "copper solution" (composition see the posting). Despite of the precipitation of copper(II)ferricyanide the solution would be applied to paper (difficulties to get a smooth and striation free surface with the brush; if a glass rod works better??), dried (cold air with a fan) and exposed for 6 min with UV and after that the print washed with running water, the print shows a reddish tint which blacks which are different from the cuprotype before.
>> If I find a way either to get a nice spreading of the "emulsion" or to avoid the precipitation of copper(II)ferricyanide (alternativ make it colloidal, so that this stuff is not disturbing anymore) it would be a nice cyanotype-mix for reddish prints.
>> Alt-photo-process-list | altphotolist.org
> Alt-photo-process-list | altphotolist.org
More information about the Alt-photo-process-list