I've not tested my UV BL tubes, but I haven't used them for months, anyway. The LEDs, despite this shortcoming, are so far superior in terms of sharpness of the prints that I'm probably not going to bother with tubes anymore.
I sensitized the cyanotype from the previous session, re-registered the positive, and re-exposed it. The cyanotype blue survives the initial coating but is gone by the end of exposure. Presumably the existing pigment is being donated to the cuprotype, perhaps contributing to density. Washed, toned in 'complex' toner, washed, and finally iron toned. Instead of the listed formula, I concocted something using ferric nitrate, sodium chloride, sodium sulfate, and muriatic acid. The toning effect seems similar.
Top to bottom: original cyanotype; cuprotype overprint, complex toned; previous plus iron toning
View attachment 361152
The results would have been pretty magnificent had the highlights remained clearer after the reprint & first toner. Mystery fog... perhaps chemical or even just simple overexposure. As with any print 'it looks better in the hand than on the scan'.
The paper is holding up very well so I'll try to see how many processing cycles I can put it through before it's totally wrecked. Fun stuff
Indeed. Thanks for sharing.Anyway, Copper Sulfate with Cyanotype stays interesting.
Not a good approach to alt process and I am not saying that because I wrote the instructions!!!I wonder if anyone could help, I'm also struggling with the Cuprotype process. I started out making some last week, and the first batch, following the recipe found here https://www.alternativephotography.com/cuprotype-process/
The first time I mixed the chemistry I was a little haphazard and probably didn't measure exactly, but I didn't take notes. The first prints were done using a salt printing negative and a professional exposure unit. 30 minutes exposure gave a weak, but useable print. 45 minutes exposure gave a good print. It was suggested to me to try double coating, so I added a second coat of chemistry, and these gave reasonable D.Max at 30 minutes, better than the single coated paper.
A few days later I tried to repeat this, I measured chemistry as follows:
5g FAC made up to 10g with water
3g Copper Sulphate made to 30g with water
2g Hypo made to 20g with water
I combined the FAC and CuSO4 and then mixed in the hypo. I applied with a brush and tried both single and double coating paper. After 30 minutes exposure the image was weak, severely lacking highlight details. After 1 hour of exposure I got a print similar to the one I had previously but with better contrast.
Thinking the UV bed or FAC might be playing up I've tested a cyanotype with the same salt negative, after 20 minutes of exposure the shadows had started to reverse. On development the cyanotype looks good, although with thin highlights perhaps from the dense salt negative. A normal Cyanotype negative on this bed takes 12 minutes for maximum black, so considering the negative density this seems ok to me.
I read this entire thread looking for an answer, I've tried making a solution of
5g FAC/3g CuSO4/3g Hypo in both 45ml and 60ml of solution, and with and without Tween 20. The thinner solution with tween was the best, although I think I added too much tween as there were small bubbles on the surface while coating. After 30 minutes of exposure the prints without Tween almost completely washed out, worse than the previous attempts. With 45minutes exposure the tween print was OK, but still very thin, thinner than the previous two printing sessions!
I've noticed the instruction of leaving to dry 5 minutes until the paper looks matt, mine goes matt within 1-2 minutes. I'm using Fabriano Unica which I know should be fine for the process (not pretreating the paper in any way). Negatives are made on an Epson Inkjet with Permajet Digital Negative Film which is the best I've been able to source in the UK and works well for salt prints.
I wonder if anyone could help, I'm also struggling with the Cuprotype process. I started out making some last week, and the first batch, following the recipe found here https://www.alternativephotography.com/cuprotype-process/
The first time I mixed the chemistry I was a little haphazard and probably didn't measure exactly, but I didn't take notes. The first prints were done using a salt printing negative and a professional exposure unit. 30 minutes exposure gave a weak, but useable print. 45 minutes exposure gave a good print. It was suggested to me to try double coating, so I added a second coat of chemistry, and these gave reasonable D.Max at 30 minutes, better than the single coated paper.
A few days later I tried to repeat this, I measured chemistry as follows:
5g FAC made up to 10g with water
3g Copper Sulphate made to 30g with water
2g Hypo made to 20g with water
I combined the FAC and CuSO4 and then mixed in the hypo. I applied with a brush and tried both single and double coating paper. After 30 minutes exposure the image was weak, severely lacking highlight details. After 1 hour of exposure I got a print similar to the one I had previously but with better contrast.
I read this entire thread looking for an answer, I've tried making a solution of
5g FAC/3g CuSO4/3g Hypo in both 45ml and 60ml of solution, and with and without Tween 20. The thinner solution with tween was the best, although I think I added too much tween as there were small bubbles on the surface while coating. After 30 minutes of exposure the prints without Tween almost completely washed out, worse than the previous attempts. With 45minutes exposure the tween print was OK, but still very thin, thinner than the previous two printing sessions!
I haven't attempted a tricolour cyanotype as I haven't found a toner yet that I have access to that could give the magenta, but then I discovered cuprotype, so decided to try with that.Your experiments in CMY cuprotype remind me of this: https://www.photrio.com/forum/threads/showcase-for-your-hcwps.199853/post-2801289
I got interested in cyanotype a couple of years ago as an alternative, fairly safe, simple, and affordable way to do something a bit more arty with my photos rather than just have them sit on my PC.
I know a bit about chemistry, and knowing that silver is what is used for traditional photography, wondered if there were any other transition metals that are photosensitive, and that led me to the alternative photography website. Turns out there are a few, but either they're expensive, toxic or both, but cuprotype caught my attention because it's cheap and fairly non-toxic.
The yellow and pink results interested me, as I can't get those so easily with cyanotype - well yellow to an extent, but the other toned results are not so different to what I could achieve with cyanotype.
What really interested me was the possibility of combining processes to get duotone or more in a single image.
Looking at the yellow and pinkish red, of cuprotype untoned or toned with KFeCN and knowing that I can tone cyanotype to get a reasonable black, I wondered if I could make CMYK images.
I've enjoyed experimenting with toned cyanotypes and that extends the range of possibilities, but they're still monochrome. I've hand coloured a few using watercolour pencils or paints, but though lightfast, since they're watercolour, they're not waterproof.
This isn't ink, it's photosensitive chemistry, and I think I read here or on alternative photography that order matters, as cyanotype chemistry applied over cuprotype can convert cuprotype to cyanotype.
Here's an effort made from 3 separations:
Black: Cyanotype toned with instant coffee for about 5 minutes. Gives more of a blue/black than true black, but I found it stains the paper less than other toners.
Blue: Traditional cyanotype
Yellow: Untoned Cuprotype using CuSO4, FAC, Sodium Thiosulfate recipe.
I deliberately brushed the layers on a bit irregularly, as I want more of a painterly look than a 'perfect' reproduction. I have an inkjet for that!
Actually everything is done on a budget. I use an old laser printer someone donated to me, and a sheet of glass out of an old fridge to hold the negative in place during exposure - hence the scratch marks on the image, and some blotches from where the printer drum is getting tired.
I exposed in the sun. Being in the southern hemisphere with clear skies and close to the ozone hole, there's plenty of UV around most of the time.
View attachment 382330
Second image is CMY (I didn't bother doing a black separation)
I did cyanotype first, then cuprotype and toned it with KFeCN, then finally cuprotype without toning.
I realised subsequently after reading here, I should have washed longer to remove residual unexposed cuprotype chemicals, and I'm not sure whether the CMYK separations in Photoshop are ideal for this and whether there's a better way to produce negatives, but at least I've demonstrated that the principle works.
Also, I suspect the cuprotype emulsion ends up toning the cyanotype, so I'm not sure if there's a way to retain a blue sky.
I was careful to select images where there was clear separation of colours in different parts of the image so they'd be more likely to work.
Image below is a cherry tree in blossom on a grassy hillside, so it actually was pinkish. The top image had dry grass and the structure actually is golden yellow.
Certainly not photorealistic colours, but I still like the aesthetic, and will keep experimenting.
I'd be interested to know if anyone else has tried this kind of process and what sort of success they've had.
View attachment 382333
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