Van Dyke bleaching?
Ok... so the prints look great through the water developer - but fade directly on fixing.
My suspicion is that the thiosulfate fixer is bleaching (when done as in the Bostick & Sullivan directions). At about 1 minute it maxes out in density and begins to lighten. So the question is - what's the minimum fixing time for this process that won't lead to self-destruction later?
Or is something else going on here? 50g of hypo seems like a lot for 1L of water.
1-2 minutes in 2% plain sodium thiosulfate is more than enough. One good remedy for bleaching in fixer is to tone the print in gold, platinum or palladium. (Before fixing!) That way, you'll get very stable and beatiful prints. Plain vandykes aren't much archival, or, lets say they are much more vulnerable to attacks from the environment. A nice, good working, long lasting and relatively cheap toner would be gold-thiourea toner; it tones the print with both gold and sulfide. It will give you a darker and much more (very!) stable print.
P.S. Refresh the fixer after 3 prints to be on the safe side, or do double bath fixing and refresh after 5-6 prints.
P.S.2. Vandyke drydown is immense, totally blown highlighs (seemingly) will gain considerable density and show detail when dry...
exposure longer. i use the same hypo mix as you and i leave mine in the fixer for 4 min. no problems....
Drop it in some Viridon - works wonders!
I am with Loris. Tone the print with a gold, platinum or palladium toner before fixing. If you do you will not get any bleaching when fixing. This type toning also makes the print much more permanent.
Thanks! I have the gold toning stuff here and will try that.
Originally Posted by sanking
Dante I'm not sure if ready-made (designed for S/G printing) gold-thiourea toner is OK. I have always used the toner mentioned here:
P.S. BTW, I use anyhdrous KAuCl4 instead of the usual gold chloride compound and it works OK.
See the excerpt below:
Clerc's Thiourea Gold Toner
The solution requires no aging; it is ready for use directly after mixing. It tones highlights and shadows at the same rate so the print tones evenly and can be removed from the toning bath at any time. It keeps well and resists decomposition even after moderate use.
Gold Chloride (1% solution) 12.5 ml
Thiourea (1% solution) 12.5 ml
Tartaric Acid 0.12 gm
Distilled Water to make 250.0 ml
Sodium Chloride 5.0 gm
Make up a 1% stock solution of gold chloride by dissolving one gram of gold chloride (AuCl3HClH2O) in 100 ml of distilled water. Keep the solution in a brown bottle. Likewise, make up a 1% stock solution of thiourea. Uncontaminated, these solutions keep indefinitely. Add the thiourea solution to the 12.5 ml of gold chloride solution until the precipitate that forms is dissolved. The quantity of the thiourea solution should be slightly more than that of the gold chloride. Add the tartaric acid to 150 ml of distilled water. Add the gold thiourea solution to the acid solution and mix thoroughly. Last, add the salt, top off with water to 250 ml and stir until the solution is uniform. Bottle and label the solution.
Make sure that the tray and tongs that you use are clean. Immerse the the developed, cleared, and rinsed print quickly into the toning bath (or pour the toner onto the print). Agitate the print frequently during the toning period--five to ten minutes, depending on the condition of the toner. After toning proceeds to a satisfactory color, rinse and fix the print. Finally, wash the print for 20 minutes.
[QUOTE=Loris Medici;827735]Dante I'm not sure if ready-made (designed for S/G printing) gold-thiourea toner is OK. I have always used the toner mentioned here:
There are formulas for gold, platinum, palladium and selenium toners in my article on kallitype at unblinkingeye.com. These toners will work with Vandyke just as well as with kallitype. With gold, platinum and palladium you tone before fixing, but selenium toning should be done after fixing.
I've been using a five percent plain hypo bath for fixing, and the prints actually get darker in it.
Has anyone used regular photo fixer to fix these? I was screwing around last night, and you get the same darkening (actually, a lot more of it... to the point of making all-brown prints). Any obvious downside? Seems like it will need a lot of dilution (or a lot less exposure). Over the weekend, I am going to mix up some gold toner and the (correct) Van Dyke fixer. My experiments last week seemed to indicate that dropping the dilution to 2% solved the bleaching issue.