sanking said:
Even though the silve salts are soluble in VDB I very much doubt that it is possible to wash them all out in the short wash typically given VDB prints before they are toned or go to the fixer, so in fact there would be a lot of soluble silver salts in the print when fixing. You can definitely see result of this with selenium toning because selenium reacts very strongly with unexposed silver salts and darkens and stains the print considerably, even with washing for as long as 10-15 minutes. This is primarily the reason why toning with selenium should be done after fixing and final washing.
Sandy
Sandy,
This is one of those things that I've read people have success with but that I have not been able to duplicate. I'm speaking of toning a VDB with Kodak Rapid Selenium Toner. Even at dilutions like 1+200 I get bleaching regardless of whether the toning is done before or after fixing. In fact, I doubt that a fixing step is needed if toning is done/attempted with KRST because of its high ammonium thiosulphate content. I spoke to a Kodak rep years ago about this and also consulted the MSDS for that chemical and got a figure of about 45% ammonium thiosulphate in KRST's formulation IIRC.
I would think that using KRST "after fixing and final washing" would put thiosulphate back into the paper and that would not be good for longevity of the print.
Are you refering to results you have experienced personally with VDB and selenium toner (KRST) or are you referring to results with another selenium toner/ or kallitypes instead VDB/ or someone else's work either read or seen?
Sorry to be so questioning but this is really baffling to me. Based on my experience with KRST and VDB, I don't see how VDB wouldn't bleach in KSRT. VDB is such a simple process I can't imagine what I might be doing (or not doing) to get such vastly different results with KRST. It would be great to be able to achieve a good toning effect in KRST in VDB because it is so much cheaper than the noble metal toners.
Is your process significantly different from mine? Here's what I'm doing currently:
1) Coat standard VDB emulsion on Cranes Kid Finish ecru and dry using a hair dryer w/o heat in the dark. (I coat and process under fluorescent lighting and have never noticed any fogging. I used to coat and do the initial processing steps under red safelight but found during classroom demos that it was not needed.)
2) Recoat the standard VDB emulsion and dry as before in the dark.
3) Expose with the NuArc 26-1K for ~400 units. (This just barely bronzes step 1 on a Stouffer wedge and prints out to step 14. I'll gain about 3 steps during processing and drydown.)
4) Rinse for 3 minutes in 2% citric acid bath. (I substituted the citric acid bath for water a couple months ago per your suggestion in another thread.)
5) Fix in two successive baths of 2% sodium thiosulphate for 1 1/2 minutes each.
6) Rinse for 1 minute in water.
7) Clear in Kodak HCA for three minutes.
8) Rinse in running water 3-5 minutes
9) Tone in Clerc's gold toner for 2-5 minutes depending on freshness of toner. I tone by inspection until the desired color is achieved.
10) Wash for 15 minutes using a tray siphon (1 print at a time).
11) Air dry emulsion up on screens.
I always gain density during processing and drydown using the above method. The only time I get bleaching with VDB is when I use KRST, a stronger fixer, or when the emulsion floats off watercolor papers in the water wash.
During my multiple previous attempts to tone with KRST (between 1+ 20 all the way to 1+200), the differences in my process were the change in toners (KRST instead of Clerc's gold) either before or after fixing (didn't seem to matter as far as bleaching was concerned), and using an initial water bath instead of the citric acid.