Your experiment sounds fascinating, and you are probably not the first one to try it. The focusing issue sounds like one of the problems you would encounter, but I have a feeling that that is not the main problem with this method. I think that the main problem encountered is getting enough UV to even expose the paper. The problem with UV bulbs I have heard is there is not enough UV to expose the print in a resonable amount of time. Your idea of pointing it at the sun is a good idea. Please post your results. I am very interested.
"But what is strength without a double share of wisdom." --John Milton
"Our greatest fear should not be of failure, but of succeeding at something that doesn't really matter." --Unknown missionary
Why not do the following -- get some ortho sheet film - still readily available. Make an enlargement from your 35mm neg onto the ortho film, develop in Dektol for a few minutes, and then either use that or then contact expose onto another sheet to get a negative -- also developed in Dektol. THEN make a contact print cyanotype. Not only is this simple, it is also repeatable and not some kludge. You guys seem to want to find the hardest way to do something at times. Don't bother with a paper negative. You'll want as much UV coming through as possible. You will get great results using film. Of course, you'll have to experiment a bit to get the right exposure onto the ortho film, but actually using the Kodak print exposure overlay will work fine. Remember the engineering mantra --- KISS - Keep IT Simple, Stupid.
How can anyone consider more simple to get some ortho large format film (which is by the way unavailable since decades in the overwhelming majority of the world's countries) make two (read TWO) internegatives (with all the painful process of guessing the exposure with trial/error process, not even to mention unforseenable contrast shifts and forgetting the PITA of tray developing, and skipping over the long time needed for the emulsion to dry up which obliges to split the work over at least three days, and ingoring the progressive increase in spot and scratches) than slapping an enlarger under the sun, and even write that looking for a shortcut is stupid, is completely beyond my comprehension.
Just to mention how this is absolute common ground, I will simply quote Ed Buffaloe from his well known article "Less is more": The factor that most often inhibits people from trying the historic photographic processes is the need for a large negative suitable for contact printing. The traditional means of obtaining an enlarged negative has been to make an enlarged film positive (known as an interpositive) and then make a negative by contact. The length of the process defeats many people before they ever begin.
I know a chap who does excellent portraits. The chap is a camera.
(Tristan Tzara, 1922)
Marco -- It's not as hard as it sounds -- i have done it. Didn't take long. Of course, you have to know a little bit about the materials you are using. Obviously the simplest method is a digital scan and then make a negative on transparancy film -- that will work fine, and avoids all the rest of the screwing around. However, the original poster said he didn't have a scanner. But he does have a darkroom.
Ortho film is available from J&C, and I suspect they are getting it from Europe, so it does exist. I am fortunate to have a bunch of Kodalith in various formats.
I have no experience of them myself, but some photographic studios in the late 1850s/60s or so used to have them set into the roof, geared to follow the sun. Here is a thread from the Civil War re-Enactors wetplate forum (very interesting place) by Scully & Ostermann you might find interesting:
The first solar enlarger (1857) could print an enlarged portrait in about 45 minutes, hence the need for the enlarger to follow the suns progress through the sky.
There is also a reference on the Alt-Photo list that mentions that Thomas Eakins (1844 - 1916) made direct 11x14 enlargments in platinum from half-plate negatives, so it should be possible to get enough UV out of one - given enough time!
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If you are using resin paper you can submerge the negative print in HOT water for 5 min and then work to peel the emulsion off of the paper backing. This will give you a much thinner print, and, I would assume shorten the time needed for exposure.
Photography is transforming random distributions of photons into something more, something beautiful.
Why not contact print the 35mm neg, then mount the cyanotype print in a large mat and call it fine art. Sell it for lots and lots of money.
Alternatively, mount the print under a magnifying glass.
This may seem like a total joke, but it might actually work. I have a series of portraits and landscapes I did in 6x6 (a bit bigger than 35mm but still quite small) that are mounted in tiny frames. Some are cyanotype and others are Polaroid transfer. It makes an interesting display, especially when mounted in a cluster. People have to stand real close to see so lighting is a challenge but the reviews have always been positive.
Just a thought, but how about building something from a slide viewer? You could remount the opticsto be perpendicular to the paper, then use a fresnel aove the negative to compensate for the movement of the sun.
Personally, before going to that trouble I would go the film or paper internegative route. If you wanted to streamline that process, start with a chrome and produce a negative from that.
Much UV light is generated in flourescent lights. Perhaps the coating in the lights blocks some of it, but incandescent lights should be safer. The yellow incandescent bug lamps are better yet.
Originally Posted by rduraoc
When I did alternate processes long ago we often used enlarged half-tone negatives. Printing time was shorter than when using continuous tone negatives. Litho film for halftones might not be expensive. Finding a screen for making the halftones could be a problem, though, if you can't improvise one. If you have a way of scanning prints, you could print halftone negatives on transparancy material in an inkjet or laser printer. I haven't tried printing such negatives, and their quality didn't look very good. However, it does use common material.
Quite frankly, with only 35mm equipment, you are just plain out of luck; unless you can find some way to obtain a large copy negative with which to print. If you really want to try the cyanotype process then get some 4x5 or 5x7 film and make a pinhole camera. Use the negatives to make cyanotype contact prints. Afterwards, if you really like the results then save up for a LF format camera.