I’ve got to tell a bit more about my lumen printing, as it offered such fun during the summer break. I think somehow I came to realize what were the feelings of Henry Fox Talbot when succeeding in his first Photogenic Drawings.

It is a known fact that summertime weather in Finland is often cloudy and rainy (but low in snow, as they say ;-)) but nevertheless I managed to expose a number of lumen prints using sunny days. Exposure times were long though, as UV levels don’t get very high at these northern latitudes.

Almost any silver gelatin paper seems to work in lumen printing – each in its own way. In lumen printing the results can be quite diverse (as are plants themselves) depending on the paper type and the chemical processing. Moreover, the moisture extracting from plants in pressure against the paper may also create weird “auras” around the plant silhouette.

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Exposure on Konica EX Color Paper, which actually is made for processing with RA-4 color chemicals. Here it has been only fixed (Hypam 1+4, 1 min.) after a 3,5 hours exposure. At the time of the exposure the UV index was ca. 5.5. The surface of this paper (or actually it’s all plastic) is ultra glossy, and in lumen printing, at its best, it can produce warm, low contrast, almost golden tonality.

One of the problems in lumen printing is how to keep all those colors that were formed during the exposure. The image must be fixed in order to preserve it, but fixing itself, no matter how it is done, seems to lighten the image and desaturate the colors. Of course it is possible to keep the unfixed print in the dark, and only shortly view it now and then in dim light, enjoying the colors (although my guess is that changes in the unstable silver would slowly destroy the image anyway). And yeah, you can do as I have done here – scan the print before fixing, and use that scanned (and maybe somewhat enhanced) image for new prints. But it tastes a bit like cheating…

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Bergger Prestige paper produces quite interesting colors when exposed to UV light. On the left the print is seen right after the exposure, on the right when toned with Tetenal Gold Toner and fixed (Hypam 1+4, 1 min.).

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Here I tested a few toners, the paper was Agfa Record-Rapid. The left-hand picture is scanned from the unprocessed print, on the right the print has been cut to strips and each of them processed differently. The top strip is untoned and fixed. The second one is toned with Tetenal Gold Toner, the third one with Kodak Rapid Selenium Toner diluted 1+5, and the strip at the bottom has been toned with Lux Eterna Sulfolux sulfide toner by Hopeavedos.

Conclusions on toning in general: Not toning (fixing only) lightens the image, but can work OK if lightening is allowed. Also, with gross overexposure and fixing the print will yield delicate “golden” tone, which can be quite attractive with certain subjects. Toning with gold will increase Dmax (maximum density) and cool down the image tone. Selenium also deepens Dmax and shifts the color slightly towards red. The sulfide toner didn’t work here at all, turning everything black like it was developer.

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Jalo Porkkala: Heracleum Mantegazzianum #1, Lumen print.

An example of prolonged gold toning. In spite of long exposure (on Emaks paper) image tones were quite weak after the exposure. With a long (7-8 min.) gold toning the tones got deeper, and remarkably colder at the same time. There are also yellowish areas in this image, due to plant extracts reacting with the silver emulsion.

Another problem related to a long exposure is the plant tending to dry and stick to the paper during the exposure. The heat in bright sunshine has an effect on this too, so sometimes, after the exposure, it may be hard to separate the plant from the paper without tearing the paper.

To avoid these harms I tried to find a way to increase the paper’s speed. One possibility could be to dissolve the silver of an unexposed paper by fixer and then wash it away. The remaining gelatin base could then be hand sensitized with silver nitrate, using the salted paper or vandyke method.

Instead I decided to try the silver nitrate method straight; I had silver nitrate sensitizer left over from salted paper tests done a couple of years ago. It was the standard saltprint sensitizer (12 g silver nitrate + 100 ml water), which I further diluted 1+2 with tap water.

When I finally learned how to do this extra sensitizing properly (I used a foam brush to coat a dampened photo paper with silver nitrate in dim roomlight) the increase in sensitivity indeed was noticeable. For example, the 7-8 hours exposures on Emaks shortened to half to two hours. In addition, adding silver led up to dramatic increase in density.

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Agfa Record-Rapid paper coated with silver nitrate. Toned with gold (Tetenal) before fixing.

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Jalo Porkkala: Convallaria Majalis #6, Lumen print.

Here’s another sample of gold toning, which makes the dark tones bluish and yields a nice split tone.

By coating an ordinary silver gelatin paper with silver nitrate I can increase the paper speed and get better Dmax. But I wonder if there’s a way to preserve the produced colors so that they wouldn’t fade in the fixer? I tried sort of “desensitization” by using very diluted chemicals with very short treatment times, fixer and toner in turn, one after the other several times, with washing in between. I was hoping the short treating times would not make great changes, so I could slowly “harden” the print to stand the chemical treatments without changing too much.

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This is how Emaks looks, fortified with silver nitrate, right after 30 minutes exposure.

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Jalo Porkkala: Urtica Dioica #2, Lumen print.

This is the best I could do with preserving the colors. The print was treated several times in diluted palladium toner and fixer (Hypam 1+20) for a few seconds at a time, with water rinsing in between.

More my lumen prints