3 ms·

I convert old photo negative enlargers to UV enlargers for printing with alternative processes (cyanotype in particular). It doesn't take much space and I do i

I convert old photo negative enlargers to UV enlargers for printing with alternative processes (cyanotype in particular). It doesn't take much space and I do it out of my small European town house basement. Which also serves as my photo lab for demonstrations.

paulmd 4y ago
That's neat. What do you use as the source? A bank of UV LEDs? Never really thought about that but can you get larger "flashlight" style UV-spectrum LEDs from cree/etc? Of course you need to diffuse it and fewer larger elements are harder than more smaller elements but the output power is probably higher with the big LEDs, and I seem to remember some of the alt-processes are quite insensitive (like, leave it outside in the sun for a half hour). The other way you can do it is, of course, printing a big negative and contact printing outside. It's a little lame with film since you have to go through an interpositive to get back to a negative (unless you use positive B+W slide process or similar - but those processes aren't great either in terms of quality), but ironically those processes are now extremely accessible through digital or hybrid-digital workflows. Scan your negative, print the scan (still negative) onto a transparency, and contact print, done. Or you can take a random digital image and invert it and then print it onto a transparency. I should give laser-transparency cyanotype a go one of these days, that would be a few fun afternoons. On the "how do I put out enough UV light for cyanotype enlargment" thing, I wonder if there's a way to get flashbulbs to put out UV light. One of the reasons older flash photos don't have the modern digital "flash" look is because the whole flashbulb lights up, and then the reflector actually spreads out the light from the flashbulb, so you don't have a point source like the xenon tube, it's a highly diffused source. And it's actually relatively intense by modern standards - another weird niche where flashbulb still is viable is infrared photography, IR flashbulbs put out a pretty massive amount of light.
- lightedman 4y ago
  There are UVA flashlights with insane output already in existence. Cree does not make UV but Nichia does and has some of the best 365nm high-output LEDs out there with some of the lowest visible light output/generation. Another contender is Prolight. I have one of their 60 degree UVA LEDs in a light I use for mineral exploration, it will make things glow from almost 50 feet out, but it also has some considerable visible light generation that interferes with detecting weaker fluorescence. If you want a HUGE UVA bank, look at Wild Fire. They make UV LEDs for party places, like cosmic bowling nights, and such. One of those could likely be easily adapted to your purpose, though it might be a little pricey.
- seszett 4y ago
  Point sources work better than arrays, so I use either one or four LEDs (from LG) depending on the power needed for the application (and how much someone is willing to pay). With enough power (more than 50W or so), cooling the negative is required given the long exposure times on the order of tens of minutes, so there are more modifications to do than just changing the light assembly. Most people who do cyanotype print digital negatives with an inkjet printer as it has long been said that enlarging was not possible. Laser transparencies are too low in resolution to give good results. The advantage of digital negatives is that you can adjust the contrast curve to match the response curve of cyanotype to get the best contrast, since it's different from that of silver. But an all analog workflow is nice too.

paulmd 4y ago

That's neat. What do you use as the source? A bank of UV LEDs? Never really thought about that but can you get larger "flashlight" style UV-spectrum LEDs from cree/etc? Of course you need to diffuse it and fewer larger elements are harder than more smaller elements but the output power is probably higher with the big LEDs, and I seem to remember some of the alt-processes are quite insensitive (like, leave it outside in the sun for a half hour). The other way you can do it is, of course, printing a big negative and contact printing outside. It's a little lame with film since you have to go through an interpositive to get back to a negative (unless you use positive B+W slide process or similar - but those processes aren't great either in terms of quality), but ironically those processes are now extremely accessible through digital or hybrid-digital workflows. Scan your negative, print the scan (still negative) onto a transparency, and contact print, done. Or you can take a random digital image and invert it and then print it onto a transparency. I should give laser-transparency cyanotype a go one of these days, that would be a few fun afternoons. On the "how do I put out enough UV light for cyanotype enlargment" thing, I wonder if there's a way to get flashbulbs to put out UV light. One of the reasons older flash photos don't have the modern digital "flash" look is because the whole flashbulb lights up, and then the reflector actually spreads out the light from the flashbulb, so you don't have a point source like the xenon tube, it's a highly diffused source. And it's actually relatively intense by modern standards - another weird niche where flashbulb still is viable is infrared photography, IR flashbulbs put out a pretty massive amount of light.

lightedman 4y ago
There are UVA flashlights with insane output already in existence. Cree does not make UV but Nichia does and has some of the best 365nm high-output LEDs out there with some of the lowest visible light output/generation. Another contender is Prolight. I have one of their 60 degree UVA LEDs in a light I use for mineral exploration, it will make things glow from almost 50 feet out, but it also has some considerable visible light generation that interferes with detecting weaker fluorescence. If you want a HUGE UVA bank, look at Wild Fire. They make UV LEDs for party places, like cosmic bowling nights, and such. One of those could likely be easily adapted to your purpose, though it might be a little pricey.
seszett 4y ago
Point sources work better than arrays, so I use either one or four LEDs (from LG) depending on the power needed for the application (and how much someone is willing to pay). With enough power (more than 50W or so), cooling the negative is required given the long exposure times on the order of tens of minutes, so there are more modifications to do than just changing the light assembly. Most people who do cyanotype print digital negatives with an inkjet printer as it has long been said that enlarging was not possible. Laser transparencies are too low in resolution to give good results. The advantage of digital negatives is that you can adjust the contrast curve to match the response curve of cyanotype to get the best contrast, since it's different from that of silver. But an all analog workflow is nice too.