UV exposure units available in Europe

[ole-squint]

Hello to our members in Europe.
What sort of UV lights sources are available or that you use to expose alt process prints? I'll be spending quite a bit of time next year in France and want to continue to be able to print.
Thanks,
olesquint

 

[FotoD]

We have sunshine too. Sometimes at least.



Added:
I've bought used facial tanners. They were cheap and work well for 8x10 negatives and smaller. What kind of lights do you have in mind?

 

[ole-squint]

I use bl or blb bulbs.

 

[Ian Leake]

I'm not aware of anyone in Europe who manufactures UV light units. I see three main groups of my light integrator customers making their own light sources:

1. Fluorescent tubes - that's also what I use
2. UV LED systems - these are definitely the most fashionable
3. Using salvaged old printing systems, e.g. based around mercury lamps

 

[Niglyn]

I use a florescent uv tube and starter gear from a uv pond filter.
UV tubes, holders & starter gear are easily available from electrical trade counters.

All old cameras and lenses I buy spend some time under it, to kill off any fungus before they go near any of my other cameras or lenses.

 

[Dan Pavel]

I use a larger Phillips home tanner. It works for A3+ prints.

 

[koraks]

2. UV LED systems - these are definitely the most fashionable

This is really the way to go, currently. With a few exceptions, the generic, Chinese UV floodlights in either 400nm or 365nm wavelength will work splendidly for alt. process printing. I use the cheap ones that are advertised as 150-300W, but are in effect around 75W RMS. One will do fine for 4x5, I gang up four of them to cover 8x10" at a short distance. Increase the distance and exposure time and the setup will print bigger sizes.

Previously I used fluorescents but they're inferior to cheap LED in a few ways, notably efficiency/speed and collimation/sharpness. I have difficulty parting with my bank of Philips BL tubes, but I haven't used it in nearly a year, and before that only for some testing.

@ole-squint which process(es) will you be practicing, and is it feasible for you to send or order some stuff ahead of time so it's there when you arrive?

 

[Ian Leake]

Previously I used fluorescents but they're inferior to cheap LED in a few ways, notably efficiency/speed and collimation/sharpness.

My view is more nuanced than this.

It sounds like you are using a small, point light source. You would see the same sharpness from any point source, no?

My interest is in large light sources for large prints. You can make big prints with point UV light sources, but this is needs specialist equipment. If you are making large prints with large light sources, then LEDs have a few minuses.

e.g. Good, large UV LED systems are substantially more expensive and require more design/build expertise than fluorescent tubes. They also introduce heat management issues, especially with large light units or units in frequent and/or prolonged use. When designing your light unit you need to consider heat flow, heat sinks and cooling fans, which adds complexity and cost.

On the plus side, for platinum printing, if you have enough LEDs to significantly reduce printing times, then you may see increased Dmax because the paper dries out less. Whether you actually see this depends on your skill as a printer - most printing problems are not caused by the light unit.

Fluorescents are certainly not perfect - slow warming times are an issue, for example.

Ultimately, people should consider the needs of their process before selecting the technology.

 

[koraks]

It sounds like you are using a small, point light source. You would see the same sharpness from any point source, no?

No, I'm using the array-style units. Like so: https://tinker.koraks.nl/photography/beam-me-down-scotty-a-new-ultra-simple-uv-light-source/ But I've since switched to the same type with 365+400nm combined wavelength LEDs specifically for carbon DAS.
This makes for a quasi-collimated light source. The difference is significant: https://tinker.koraks.nl/photography/collimated-vs-diffuse-light-a-cyanotype-example/ Of course, this difference is mostly relevant for certain approaches to printing. For processes like Pt/Pd, it's not all that much of a benefit.

e.g. Good, large UV LED systems are substantially more expensive and require more design/build expertise than fluorescent tubes.

A lot has changed in the past 2-3 years.

Costs are very manageable and certainly competitive with fluorescent tubes.
The heat management issue is also not very significant with the kind of units I use. For smaller, high-powered COB LEDs, plug & play cooling and lens systems are available affordably.
Bolting an array of LED floodlights together is easier, quicker and simpler than wiring an array of fluorescents & ballasts. Things get more complex as you increase power density. High power density is however not a strict necessity for alt. process printing. A possible exception is the kind of very fine halftone screen printing on relatively thick media that e.g. Calvin Grier does, which puts high demands on the light source. Photopolymer intaglio is in the same corner, but the power requirements are far lower than for gum & carbon.

Fluorescents are certainly not perfect - slow warming times are an issue, for example.

The older types, yes. The newer (have also been around for decades, but still relatively new...) are instant-on. The Philips BL array I built some years ago is instant on and does not change much after a second in terms of output. These also allow for rapid cycling; i.e. it's fine to toggle them on and off without damaging the tubes. The older types didn't like this.

 

[Ian Leake]

No, I'm using the array-style units. Like so: https://tinker.koraks.nl/photography/beam-me-down-scotty-a-new-ultra-simple-uv-light-source/ But I've since switched to the same type with 365+400nm combined wavelength LEDs specifically for carbon DAS.
This makes for a quasi-collimated light source. The difference is significant: https://tinker.koraks.nl/photography/collimated-vs-diffuse-light-a-cyanotype-example/ Of course, this difference is mostly relevant for certain approaches to printing. For processes like Pt/Pd, it's not all that much of a benefit.



A lot has changed in the past 2-3 years.

Costs are very manageable and certainly competitive with fluorescent tubes.
The heat management issue is also not very significant with the kind of units I use. For smaller, high-powered COB LEDs, plug & play cooling and lens systems are available affordably.
Bolting an array of LED floodlights together is easier, quicker and simpler than wiring an array of fluorescents & ballasts. Things get more complex as you increase power density. High power density is however not a strict necessity for alt. process printing. A possible exception is the kind of very fine halftone screen printing on relatively thick media that e.g. Calvin Grier does, which puts high demands on the light source. Photopolymer intaglio is in the same corner, but the power requirements are far lower than for gum & carbon.



The older types, yes. The newer (have also been around for decades, but still relatively new...) are instant-on. The Philips BL array I built some years ago is instant on and does not change much after a second in terms of output. These also allow for rapid cycling; i.e. it's fine to toggle them on and off without damaging the tubes. The older types didn't like this.

That’s interesting, thank you