Copper toner formula variation? (one for the chemists)

[pdeeh]

The copper toner formulas I have found are composed of (in varying proportion)

Copper sulfate, Potassium ferricyanide & Potassium citrate

... can Sodium citrate be substituted?

 

[M Carter]

I've seen recipes where c citrate was one part and pot. the other - my notes on those pages in my notebook were something like "part 2 can be either".

Would be a simple experiment I suppose? I've mixed very small batches in the past.

While we're on the subject - I really like copper toning for some lith prints - but I struggle with borders stained pink, even with dilute toner. Anyone have any ideas?

(And now… waiting for the "but it's not archiiiiiiiival comments… 3… 2…. 1….)

 

[pdeeh]

The less archival the better, say I
Yes, I'll probably have a go anyway but it's always interesting to see what kind of answers might come up

 

[Tis Himself]

Coat any areas of the dry print that you don't want toned (i.e. the borders) with rubber cement prior to toning. Make sure the rubber cement is completely dry before toning the print. After the print is toned and dried, just rub off the rubber cement with your finger. Always worked for me and can create some unusual images.

 

[pdeeh]

Well, I made up half a litre of copper toner, substituting Trisodium citrate dihydrate for the Potassium citrate in the following formula ( as per BJP Annual 1965 p.93)

• 
  Pt. A.
  Copper sulfate 7g
  Potassium citrate 28g
  Water to 1000ml
  
  Pt. B.
  Potassium ferricyanide 6g
  Potassium citrate 28g
  Water to 1000ml
  

It works.

Whether it works the same as with Potassium citrate I've no idea.

Example attached, as close as I can get the tones in a scan.



PS can I just mention AGAIN how stupid the pop up box is that tells me I'm posting off-topic information simply because I'm using the word "scan".

GRRRRRRR

 

[Ian Grant]

I posted the (there was a url link here which no longer exists) in another post yesterday, I still have a test print somewhere but the colour was quite different to your example - close to the colour of copper metal itself like this Ilford example. I must have used Potassium Citrate which I'd have bought from Hogg Laboratory Supplies.

The formula you have is about a quarter the strength of the one I used that maybe why the toning isn't a red-copper. The BJP formula you used does say the toning passes through stages. I wouldm't have tought it would make much difference using Sodium Citrate instead of Potassium Citratre..

You can make Potassium Citrate from Citric acid and Potassium Cabonate, a 1 litre 20% solution needs 149g Citric acid and 160.64g Potassium Carbonate, you dissolve the Citric acid first then slowly add the Carbonate the reaction releases carbon dioxide, finally check the pH to make sure it's neutral.

Ian

 

[pdeeh]

I didn't have sufficient scrap prints around to test how much colour change there would be had I left it longer.
This one was only 5 or 10 mins at most, just enough to see if it worked really.
Also it's on a pre.ilford kentmere rc vc paper