With my post to the gallery (https://www.photrio.com/forum/media/dv010-jpg.71840/) I thought I’d write up my process. I’ve been working on this image for a couple weeks and posted earlier versions of it here. This is the final one that I’m satisfied with. I am an all-analog person and have a full photographic darkroom along with a nice DIY UV box. The original image is on 35mm infrared film from an image I shot in November 1976 at Death Valley, CA.
Since I am going to use multiple films and exposures, I use a registration system. I have a two-hole paper punch and punch a piece of paper. I then put two registration pins through those holes and tape them to a piece of card stock. These are my “master” pins.
I first enlarge the original image onto an 8x10 sheet of lithographic film that I have punched with the registration holes. I also cut a very small piece of the upper-right corner with the emulsion side facing me so I can always locate the emulsion side after processing. This film usually results in an image that is solid blacks and clear areas but I allow some mid-tones by developing it in Dektol diluted 1:10 (one part stock Dektol to 10 part water). I make 3 separate images, one underexposed, one correctly exposed, and one overexposed. I label these resulting positives P1, P2, and P3. After they are dry I use each one to make a contact print of it on another sheet of litho film and develop it the same, resulting in 3 negatives which I label N1, N2, and N3. It is important to note that since the contact prints are made emulsion to emulsion, the cut corners on the negatives will be in the upper-left when viewed correctly, that is, when what is on the left side of the original image is on the left in the negative..
I prepare my cyanotype paper (Bockingford HP 140) which I first soak in a 5% citric acid solution to ensure any buffering is neutralized. I let it dry and then coat with the “new” cyanotype solution and let dry. I then punch it with registration holes.
For exposure, I have a workbench in my shop (down the hallway from the darkroom) where I’ve taped down those registration pins. I locate the coated paper on the pins, with the coated side up. The next step of the process it to place the first film on the pins. I am using P3 for this and place it, emulsion side down on the pins, meaning that the cut corner is in the upper left. I cover this with a sheet of glass to keep it flat. My UV light is comprised of UV LED strips in a box (actually a wooden drawer that I repurposed for this) and it is on legs that keep the lights 12” above the paper. I place this over the film and paper, set its timer to 9 minutes (determined by previous testing) and let it go.
For processing I soak the paper in a tray of 10% sulphamic acid solution for 5 minutes, rocking the tray the whole time. It then gets placed in a running water bath for 15 minutes. Since our water has a ph of 7-8, I then give the paper a 3 minute soak in a 5% citric acid solution followed by a quick 15 second rinse in the water bath. (This final soak in the citric acid might be unnecessary but I do it anyway.)
I use a print roller (hand held) to remove water and then place the paper on a drying rack.
After it is dry, I repeat the previous process: recoat the paper, make another exposure, process and dry the paper. For the second exposure, I am using a sandwich of films P1 and N2, with the cut corners of P1 in the upper-left and N2 in the upper-right. Exposure is, again, for 9 minutes. The processing is the same as the first round.
The third exposure is done with N1 (which only passes light to the foreground of the image, and I reduce the exposure time to 3 minutes. Processing is the same except that I skip the final citric acid soak.
That’s the process I used to produce the image referenced above. It took a while to work out all the bugs but this whole “tone separation” process (also known as “posterization”) with film is something I’ve been doing for many decades, sometimes making the final image by silk screening. If you are making digital negatives for your cyanotypes, you should be able to use this same process.
Since I am going to use multiple films and exposures, I use a registration system. I have a two-hole paper punch and punch a piece of paper. I then put two registration pins through those holes and tape them to a piece of card stock. These are my “master” pins.
I first enlarge the original image onto an 8x10 sheet of lithographic film that I have punched with the registration holes. I also cut a very small piece of the upper-right corner with the emulsion side facing me so I can always locate the emulsion side after processing. This film usually results in an image that is solid blacks and clear areas but I allow some mid-tones by developing it in Dektol diluted 1:10 (one part stock Dektol to 10 part water). I make 3 separate images, one underexposed, one correctly exposed, and one overexposed. I label these resulting positives P1, P2, and P3. After they are dry I use each one to make a contact print of it on another sheet of litho film and develop it the same, resulting in 3 negatives which I label N1, N2, and N3. It is important to note that since the contact prints are made emulsion to emulsion, the cut corners on the negatives will be in the upper-left when viewed correctly, that is, when what is on the left side of the original image is on the left in the negative..
I prepare my cyanotype paper (Bockingford HP 140) which I first soak in a 5% citric acid solution to ensure any buffering is neutralized. I let it dry and then coat with the “new” cyanotype solution and let dry. I then punch it with registration holes.
For exposure, I have a workbench in my shop (down the hallway from the darkroom) where I’ve taped down those registration pins. I locate the coated paper on the pins, with the coated side up. The next step of the process it to place the first film on the pins. I am using P3 for this and place it, emulsion side down on the pins, meaning that the cut corner is in the upper left. I cover this with a sheet of glass to keep it flat. My UV light is comprised of UV LED strips in a box (actually a wooden drawer that I repurposed for this) and it is on legs that keep the lights 12” above the paper. I place this over the film and paper, set its timer to 9 minutes (determined by previous testing) and let it go.
For processing I soak the paper in a tray of 10% sulphamic acid solution for 5 minutes, rocking the tray the whole time. It then gets placed in a running water bath for 15 minutes. Since our water has a ph of 7-8, I then give the paper a 3 minute soak in a 5% citric acid solution followed by a quick 15 second rinse in the water bath. (This final soak in the citric acid might be unnecessary but I do it anyway.)
I use a print roller (hand held) to remove water and then place the paper on a drying rack.
After it is dry, I repeat the previous process: recoat the paper, make another exposure, process and dry the paper. For the second exposure, I am using a sandwich of films P1 and N2, with the cut corners of P1 in the upper-left and N2 in the upper-right. Exposure is, again, for 9 minutes. The processing is the same as the first round.
The third exposure is done with N1 (which only passes light to the foreground of the image, and I reduce the exposure time to 3 minutes. Processing is the same except that I skip the final citric acid soak.
That’s the process I used to produce the image referenced above. It took a while to work out all the bugs but this whole “tone separation” process (also known as “posterization”) with film is something I’ve been doing for many decades, sometimes making the final image by silk screening. If you are making digital negatives for your cyanotypes, you should be able to use this same process.
