Clerc's gold toner with citric acid

[NedL]

Clerc's book Photography Theory and Practice contains a number of "recipes" for toners, mostly in the context of silver printing-out papers. It's kind of interesting that the gold toner with thiocarbamide and salt is the one that has his name attached to it these days, even though he described a number of different toners.

In his description of the thiourea toner, he says you can use either tartaric acid or citric acid ( in equal quantities ) and that the tartaric acid version is better for gelatin-based POP, while the citric acid version is better for collodion paper. I know his toner is popular in various iron-silver processes and I'm wondering if anyone has tried the citric acid version?
( I'm making Namias' sepia prints, which are similar to VDB with citric in place of tartaric, so there is a kind of synergy in using a toner with citric instead of tartaric )

Along the same lines, I'm not 100% sure I'm remembering this correctly, but I think Sandy King's VDB instructions had a version of thiourea gold toner that was almost the same but without the salt. I'd be curious to hear anything about that too. I wonder what function the salt plays.

Finally, Clerc's toner is pretty strong. If I make it up full strength, I'd expect 12ml to contain plenty of gold to tone a 7x11 image ( obviously depending on how much darks there are )... and I'm starting with 5x7 prints these days. I'm good at using small quantities of toner but 6ml is really pushing it. From people who've used it, is it like other gold toners in that it's fine to use it diluted but just takes longer? I'll be making it up 1-shot from separate bottles of gold chloride, thiourea and tartaric or citric acid ... if I make a more dilute toner, I'm not sure if these should be put in equal quantities into 2% NaCl solution or if I should keep the salt in proportion to the other ingredients. If you use it diluted, what do you do?

 

[CreationBear]

I'll be very interested in the responses you get--I'm gearing up to explore gold-toned VDB's pretty soon. As a newbie, though, I was curious if anyone had any input on how the Bostick&Sullivan two bottle set of gold/ Ammonium Thiocyanate compares to Clerc's formula.

 

[NedL]

I'll be very interested in the responses you get--I'm gearing up to explore gold-toned VDB's pretty soon. As a newbie, though, I was curious if anyone had any input on how the Bostick&Sullivan two bottle set of gold/ Ammonium Thiocyanate compares to Clerc's formula.

I've used the thiocyanate toner quite a bit, but I haven't tried thiourea toner yet. Over the next couple months I should hopefully be able to say something about that! I'm hoping for a little more black or blue/black and a little less purple and purple/grey but we'll see! I'm waiting to start until I have some new bottles ( supposed to arrive tomorrow ) because I don't want to deal with the powdered thiourea more than necessary... once it is in solution it will be easier to handle safely.

I'm also planning to substitute some ammonium ferric oxalate for some/all of the ammonium ferric citrate and see if it changes how platinum toning works with these.

hope you can join in the fun!

 

[CreationBear]

I'm hoping for a little more black or blue/black and a little less purple and purple/grey but we'll see.

Excellent, I'm expecting a steep learning curve but there's a whole Hermes Trismegistus alchemical vibe to these alt processes that has me intrigued. Look forward to hearing/seeing your results.

 

[Herzeleid]

Hi Ned,
I am not sure if it clear your questions, I will share my observations. I have used both thiourea and thiocyanate toners. Both are equally good, but kodak gp-1 gives blue tones, I prefer the purplish tones of thiourea toners. I use the toner as one shot, I prepare 25ml per 8x10 print. I sometimes add extra water to clean the beaker and final amount in tray is diluted it takes slightly longer. Most of the toning action is finished in first few minutes.
I always prepared Clerc's toner with tartaric acid never tried citric acid, but there is Lawless' thiourea toner which uses citric acid. Lawless' toner can sometimes give duotone effects. I am experimenting with thiourea toners using different acids and ratios, I have seen almost neutral tones in my results.

 

[CreationBear]

That's very helpful to me, Serdar--thanks! One of the things I'm anxious to learn is--especially if one is going for deep blacks--is whether the toner chemistry is relatively more important than worrying about paper moisture content. (I'm beginning to think that there are a lot of "necessary but not sufficient" variables, though.)

 

[Herzeleid]

Clerc's toner uses 0.5 grams of thiourea per liter of toner, Lawless uses 3 gr per liter. Although citric acid is stronger than tartaric acid Lawless formula uses more acid. I think that has to the with the final ph of the solution. Clerc's seems more dilute on paper but I cannot say there is a discernible difference in dmax. Both thiourea toners and the thiocyanate toner works quite well. The amount of silver deposit and the ph of the toner has more effect on the toning than the relative humidity during printing.

 

[NedL]

Thanks Serdar, I was hoping my post might get some discussion like this. I will look up Liam Lawless' toner.

In my first post, I made a mistake. The thiourea toner in Sandy's VDB article on unblinking eye is precisely the same as Clerc's thiourea gold toner. It was his kallitype article that had "gold toner number 2" which is almost the same but with no salt added. Of course now I will try with and without salt to see what happens.

My bottles arrived yesterday and I toned a print this morning. I used the equivalent of 12ml Clerc's full-strength, but diluted to be 40ml in all. The toning went pretty quickly and I couldn't notice any changes after about 10 minutes or so. I used citric acid this time but plan to try all the possible combinations. I left it in for a full 45 minutes because I want to see "toned to completion". Waiting for full dry-down before evaluating it. I'll post whatever I learn into this thread.

Edit: for those interested, Lawless' thiourea toner has 6 times as much thiourea and twice as much citric acid but no salt. You can find it here. Also, he points out that the toner may turn some of the original silver into silver chloride ( for POP, but probably true for any silver image ), so if you are toning after fixing, it might be important to fix again. The print I toned this morning was already made and fixed, and I did not do this extra step.