MordanÃ§age is a special post-printing process where the silver emulsion of a black&white photograph is bleached and “softened” in a solution containing copper chloride and hydrogen peroxide. The process is quite old, it was developed in 1890s. In the literature of that time it was referred to as “bleach/etch” or “gelatin relief” and such. The name “mordanÃ§age” comes from Jean-Pierre Sudre, a French photographer, known for his experiments with photographic chemistry, among other things. There is a good overview of the process by Christina Anderson on the Unblinking Eye website.
The Mordancage solution is used to bleach and partly dissolve the photographic emulsion, so that parts of it can be totally rubbed away, and the darkest parts may lift off from the paper base. After bleaching the image is redeveloped in a paper developer or toner. The image will reappear as positive or negative, or both, depending on the degree of bleaching, washing and rubbing the print, and also on the strength of the peroxide in the solution.
The mordancage process can be done in normal room lighting. The images to be mordancaged can be freshly printed and still wet, or you can use dry prints made beforehand. In this experiment we were using prints that were made on Bergger and Forte fiber base papers a couple of weeks before.
Hydrogen peroxide 30 %
was diluted 1 + 1 with water to make approx. 15 %.
A and B mixed together in equal parts just before use.
Mix and use the working solution only in well ventilated room!
2. Rinse in water for a few minutes. At this time the emulsion can be rubbed lightly with fingertips (wearing gloves), soft brush or sponge.
3. Redevelop: Dektol 1 + 4, 2 – 4 minutes, as need be.
4. Rinse in water again (more of the emulsion may lift off).
5. Standard fixer (we used Agfa Agefix), if possible without totally removing the emulsion. For more effect the process may be done again from step 1.
6. Final wash for 5 – 10 minutes (carefully!), if possible without totally removing emulsion.
Here the darkest tones started floating in the developer – I wanted to keep them in the picture, so I didn’t fix at all, and washed very carefully only for a few minutes.
This one is on a Bergger paper, which seems to let maximum blacks float easily. The print is unfixed and gently washed.
To make another quick “Lumen” test for UV-blocking properties of an inkjet transparency, printed with an Epson 3800, we exposed a sheet of over-age Emaks paper through the printed film (as in the previous test on 28 Feb) in our UV-box for several hours during two days. The result is below (the color shift is quite interesting):
There really is only one possible patch producing the lightest tone on this paper, corresponding to this particular “neon green” on the transparency: 0, 255, 170.
How will laser printers perform at the UV-blocking test then. Not very well, we can tell you:
None of the color densities that the printer (Canon iRC3200) could output on it’s general use OHP transparency can’t hold UV-light, it will penetrate through all the hues almost equally well.
Now we are just waiting for the sunny spring days to come soon (with light rich in UV), so we can load our printing frames and leave them outside to expose some Lumen for us … ðŸ˜‰