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koraks
15-Sep-2016, 14:33
I was wondering if anyone does this. I'm talking about toning Van Dyke brown prints with thiourea toner - not thiourea-gold, but regular thiourea toner as used for sepia toning silver gelatin prints.

A few weeks ago the thought came to me that it should be possible, although it didn't seem to make much sense to tone already brown prints with a sepia toner. Yet, some color shift seemed likely and possibly slightly better keeping properties of the print due to protection of the silver particles by binding them with sulphur. At least, that's what my tiny brain could come up with and I had no way (still don't) of verifying this from a theoretical viewpoint. Google turned up nothing - only references to thiourea-gold toners. I have no books on alt processes, so that didn't help either.

So I just tried it. I have two separate solutions to make up a sepia toner: a ca. 10% thiourea solution and a 10% NaOH solution. I first tried it with roughly equal amounts of both, diluted further to about 1+1+5. I tried toning before and after fixing. Before fixing resulted in severely fogged highlights; after fixing as well, but a little less badly so. The image tone shifted to a very dense, rather neutral and slightly metallic black in the shadows and an unattractive greenish tone in the mid tones and highlights, a bit like strong sepia toning taken too far. The dmax was appealing, image tone wasn't.

I then tried the opposite: acidifying the thiourea slightly by adding a small amount of 40% citric acid instead of the NaOH. This renders the toner virtually inactive. Didn't work too well either.

Then I decided on seeking out the middle ground. Roughly 1+0.3+5 of 10% thiourea+NaOH+water. Toning with this toner after fixing shifts the reddish town of the wet print to chocolate brown, with the yellow tint in the midtones and highlights shifting to more neutral brown as well. Upon drying the prints end up rather neutral, but a bit warm (brown with no apparent reddish tones). Dmax is good and there's no silvering / metallic sheen in the blacks. I quite like the results but have no clue about image permanence, having tried this only recently.

Edit: note that I skip the bleach step that is required with silver gelatin prints. Haven't tried it but my bet is that it will all but fade the print entirely, although theoretically it could work if absolutely no fixer remains in the paper and agitation and bleach time are kept to a minimum. A very dilute bleach also seems a good idea, but I'm not sure if there would be any benefit in adding a bleach step.

Has anyone else tried it? Does anyone do it regularly? What are your experiences? Can anyone comment on the chemistry that's going on?

koraks
3-Oct-2016, 00:46
So...nobody tried this? Does anyone have any thoughts to share, or even speculations? I'd love to hear about them!

Jim Noel
3-Oct-2016, 13:51
I occasionally tone my VDB prints, especially the nudes. When I do I always use thiourea gold toner, and never bleach. Nor do I add an acid or base, i just use it as mixed to improve the skin tones. I might add that I use 15 ml to tone a 5x7 print,using the toner as a one shot. This guarantees consistency.

koraks
4-Oct-2016, 01:01
Thanks for responding; I occasionally use a thiourea good toner, but I'm curious if anyone else also uses a thiourea sepia toner.

Raghu Kuvempunagar
27-Aug-2020, 04:57
Hi @koraks,

I know this is an old thread, but curious to know if you pursued this idea further. Can you share a pic of the vandyke print that you tuned with thiourea if possible? Thanks.

Gary Beasley
27-Aug-2020, 05:14
I have tried mixing a drop or two of gold chloride solution into the sensitizer and getting a colder tone from the van dyke as well as a bit more detail showing in the highlights. I’ll have to try the thiorea, sounds interesting.

koraks
27-Aug-2020, 05:59
Hi @koraks,

I know this is an old thread, but curious to know if you pursued this idea further. Can you share a pic of the vandyke print that you tuned with thiourea if possible? Thanks.

I'm afraid I haven't; in terms of toning alt. process prints, I stick to gold toning these days. I haven't done much additional work on sepia or selenium toning. Also, I have moved largely away from Van Dyke towards salted paper because I prefer its smooth tonal scale to the more S-shaped curve of Van Dyke.

Raghu Kuvempunagar
30-Aug-2020, 02:43
I'm afraid I haven't; in terms of toning alt. process prints, I stick to gold toning these days. I haven't done much additional work on sepia or selenium toning. Also, I have moved largely away from Van Dyke towards salted paper because I prefer its smooth tonal scale to the more S-shaped curve of Van Dyke.

Ok, thanks.

revdoc
30-Aug-2020, 14:24
I'm not koraks, but I did try sepia toning a VDB print a while ago. I used a finished print (fixed and dried) and followed the usual process: bleach then redevelop with thiourea. It worked, in the sense that the bleached print redeveloped as expected, but the result was a very yellow-brown print that I didn't like aesthetically.

Raghu Kuvempunagar
7-Sep-2020, 00:28
I'm not koraks, but I did try sepia toning a VDB print a while ago. I used a finished print (fixed and dried) and followed the usual process: bleach then redevelop with thiourea. It worked, in the sense that the bleached print redeveloped as expected, but the result was a very yellow-brown print that I didn't like aesthetically.

That's interesting! Thanks for sharing your experience. Is it possible to share a picture of Thiourea toned VDB print if it is not too much of an effort?

koraks
7-Sep-2020, 08:08
I'm sorry, but I don't think I still have the print in question. At least not where I can easily find it, and most likely I tossed it.

Raghu Kuvempunagar
9-Sep-2020, 01:29
I'm sorry, but I don't think I still have the print in question. At least not where I can easily find it, and most likely I tossed it.

No worries! I knew it was a long shot.

koraks
9-Sep-2020, 02:07
I may do a new one some day, but as it is, not enough time and already a backlog of things I want to do :)

revdoc
21-Sep-2020, 01:12
Much to my surprise, I found the VDB print that I sepia toned a while back; it turned up when I was going through my stack of papers and film. Here's a scan... the colour you see is pretty accurate, and should show you why I don't like it.

The original print is pretty dark, so maybe this wasn't a good choice to test this process. All that shadow looks pretty bad when it's a dull mustard yellow.

Added after I originally posted this: I used the standard sepia toner process. I.e., I bleached the image with ferricyanide, potassium bromide ans sodium carbonate; then I redeveloped with thiourea and sodium hydroxide. The final colour can be controlled in redevelopment by changing the thiourea/hydroxide mix. I think for that I chose a mid-brown ratio. This is the reference I used:

http://home.alphalink.com.au/~simgrant/jackspcs/tpt.htm

207952

Raghu Kuvempunagar
21-Sep-2020, 11:05
Much to my surprise, I found the VDB print that I sepia toned a while back; it turned up when I was going through my stack of papers and film. Here's a scan... the colour you see is pretty accurate, and should show you why I don't like it.

The original print is pretty dark, so maybe this wasn't a good choice to test this process. All that shadow looks pretty bad when it's a dull mustard yellow.

Added after I originally posted this: I used the standard sepia toner process. I.e., I bleached the image with ferricyanide, potassium bromide ans sodium carbonate; then I redeveloped with thiourea and sodium hydroxide. The final colour can be controlled in redevelopment by changing the thiourea/hydroxide mix. I think for that I chose a mid-brown ratio. This is the reference I used:

http://home.alphalink.com.au/~simgrant/jackspcs/tpt.htm

207952

Hey! This is so nice of you! Thanks a lot!!

revdoc
22-Sep-2020, 01:48
You're welcome!