How can I fix an image on a pseudo contact print?

[DannL]

I've known for some time that a piece of variable contrast paper tossed into the sun will change colors in a short time. Sometimes it will turn a purple/black. Playing off this idea I decided to make a contact print using a paper negative and an old piece of Kodak Polycontrast paper. A 40 watt bulb in a contact printer and in about 20 minutes I had a nice dark purple positive (without chemicals). I'd like to fix the image permanently, but regular chemical fixer dissolves the image within a few seconds. Any ideas?

 

[dpurdy]

You could take a photo of it with color film. Or scan it.

 

[DannL]

You could take a photo of it with color film. Or scan it.

It's Catch-22. I realize this is a slight exaggeration, but this is basically what is taking place. The more you exposed the entire print to light, the darker the print becomes, and overall contrast is then reduced. For this reason I'd like to fix the original print chemically or otherwise.

 

[Photo Engineer]

Which fixer did you use?

PE

 

[DannL]

Which fixer did you use?

PE

I'm fairly sure this batch is Kodak fixer diluted from the recommended stock solution. The same dilution I would use with film and normal prints. Not being at home, I'll need to reverify that. To non-scientifically test the effects of the fixer on a contact print, I placed a sample print in a tray filled with tap water. I let it soak for about 30 seconds. Then I dumped only several tablespoons worth of fixer in the tray on top of the print and sloshed it around. That weak enough dilution of fixer, by itself, destoyed the visible image. All that was left was a very faint yellow cast image.

I am curious what is happening to create this purple/blackish image just from exposure to light. I guess this would be similar to POP.

 

[Photo Engineer]

Acid fixer will destroy this kind of image more rapidly than alkaline or neutral fixers. The best fixer is to use Sodium Hypo pentahydrate at about 50 g/l with about 10 - 20 mg/liter of benzotriazole (BTAZ) in it if it dissolves the image without the BTAZ. There are other addenda that might help if the BTAZ does not.

PE

 

[Mateo]

I've done exactly what you're doing and the trick was plain hypo exactly like Ron said. I didn't use any BTZ and the image did lighten considerably. The dark purple will be light purple/pink. Old papers seem to work good for this and it isn't just variable contrast papers, graded works too.

 

[Photo Engineer]

Mateo;

A tad of an antifoggant like BTAZ or Bromide or iodide or PMT will change the tone a tad but reduce the lightening. The antifoggant goes on the blue silver and inhibits the fixer, but then changes the tone.

PE

 

[DannL]

Acid fixer will destroy this kind of image more rapidly than alkaline or neutral fixers. The best fixer is to use Sodium Hypo pentahydrate at about 50 g/l with about 10 - 20 mg/liter of benzotriazole (BTAZ) in it if it dissolves the image without the BTAZ. There are other addenda that might help if the BTAZ does not.

PE

Does this type of alkaline fixer come ready-made, or should I be looking for the raw materials? Sodium Hypo***** pentahydrate? Thankya mucho.

 

[Photo Engineer]

Just look at a place like the Photographers Formulary or other chemical supply houses for Sodium Hypo Pentahydrate. It is inexpensive. There is nothing ready made like this AFAIK.

PE

 

[Akki14]

What you're doing is basically a lumen print. This page has more info on keeping the colours and fixing
http://www.alternativephotography.com/process_lumen.html

 

[Justin Cormack]

I havent tried but I think treat like POP - wash first and tone before fixing. Harder than POP as you have to do all this under safelight. There is a nice darkroom book that discusses POP on DOP paper but I didnt buy it when I saw it.

 

[DannL]

What you're doing is basically a lumen print. This page has more info on keeping the colours and fixing
http://www.alternativephotography.com/process_lumen.html

Yes, this is the process, exactly. And I stand corrected. I have been using Ammonium Thiosulphate as a fixer and not the Kodak's Sodium Thiosulphate based fixer. The bleaching effect is in keeping with the findings described by Marek. In my case the bleaching is severe. Another interesting result came from coating the paper in a solution of iodine, washing and drying, and then followed by exposure. But, further experimentation is required on that front.