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Experiences with 365nm UV flashlight for Cyanotype.

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Jan de Jong

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Out of curiosity I recently bought a cheap (10 Euro) UV flashlight, it claimed to be 365nm and 30Watt. Not that it matters, I wanted to see if it would have any effect on Cyanotype emulsion or other UV processes. In any case as soon as it arrived I prepared some paper with Cyanotype emulsion for my normal photo-gram exposure. I found quick that even the shortest flash, which I do on close range like direct on the glass or a few mm over the subject would lead to blue. So that was a good start. Taking it a bit further it allows to work on a piece of paper in sections and changing the darkness by repeated or longer or closer shining the light. Working gradually to fill the paper.
A disadvantage is that visually there are only a few tones that stand out, ie the yellow of the unexposed, the blue of short exposed and then the bronze color when longer exposed. You have to remember a bit where you were to make the very deep blue. The good thing is that because the light is intense due to keeping it very close to the paper the total time to work an image is about 2 minutes.

Overall I think these flashlights can be used for more abstract but also very good to do some burning on normal prints where a negative is used. I was surprised by the extra possibilities this opens.

WhatsApp Image 2025-11-24 at 22.05.11.jpeg
WhatsApp Image 2025-12-13 at 17.59.59.jpeg


The left image was made using a dried fern leaf and tracing over it to get the silhouette only. The right image, I would call it a mountain view illusion was created by just using 2 pieces of paper as mask and one of them had 2 small holes in it to create the "birds" and "trees".
It is a way of working very quick, for example the right image was created in 2 minutes and including rinsing 30 minutes later the print was drying.

Just wanted to bring this in the group for those who are not aware or were curious if these flashlights re any good.


cheers
Jan.
 
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Jan de Jong

Jan de Jong

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Thank you Ansel, Koraks and Raghu !

Hope anyone finds some use in this, it opens a lot of possibilities even with negatives for selective burn etc.
Here 2 more from today.
WhatsApp Image 2025-12-14 at 20.31.45.jpeg


WhatsApp Image 2025-12-14 at 10.31.17.jpeg


cheers
Jan.
 
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Jan de Jong

Jan de Jong

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Very creative prints! Feels as if one is a dreamscape.

Have you tried CyanoLumen with your approach?
Not yet, I had initially only in mind to see if I could use the UV-flashlight for doing experiments on emulsions etc. I did not think it would be so effective. So yes next should be to try further on Cyanolumen or the Cuprotype etc.

The figurative approach currently is I guess just playing with this and is fun because it is really fast.
Total exposure and composition is a matter of minutes only, because of keeping the light at such close range.
 
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Jan de Jong

Jan de Jong

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Have you tried CyanoLumen with your approach?
After your suggestion here a Lumen, same method. On Agfa multi-grade. 10x15cm
- It us much more sensitive so almost to fast to work with the UV-flashlight. I would have to cover it a bit.
I show you the original, undeveloped after my Segmented layered exposure. In silver this is to crude, but a good experiment.

WhatsApp Image 2025-12-15 at 20.44.15.jpeg
WhatsApp Image 2025-12-15 at 21.10.17.jpeg

right is after very diluted development in old developer and then fixing. It stays pink-red.
-contrast is not so striking as with cyanotype
-my UV is to aggressive and not fine pointed for this, have to blend it.
-more practice needed for better results
- pictures are a bit on the dark side, in real it is slightly brighter.
- total exposure about 1 minute.

cheers
Jan.
 

Raghu Kuvempunagar

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Very nice results! Lumen is in general produces low contrast results compared to Cyanotype, but gives interesting colours. That the exposure is in minutes is very encouraging for Lumen, usually it takes several hours in the sunlight.

Thanks for doing the experiment and sharing your results. Much appreciated.
 
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Jan de Jong

Jan de Jong

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Very nice results! Lumen is in general produces low contrast results compared to Cyanotype, but gives interesting colours. That the exposure is in minutes is very encouraging for Lumen, usually it takes several hours in the sunlight.

Thanks for doing the experiment and sharing your results. Much appreciated.
Yes it works fast so after the previous, I put a dried Fern leaf under glass and manually traced it. Here you can see I get more contrast. Here just after exposure. These then would have to be kept out of the light. Advantage it is much faster indeed this was again about 1 minute total.
WhatsApp Image 2025-12-15 at 21.42.20.jpeg
 
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Jan de Jong

Jan de Jong

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Thank you Raghu, now I have to explore the lumen and the UV-torch 😂

taking the Agfa Multigrade 10x15 cm, wetting with hand soap to make it alkaline, dunking the leaf in vinegar hoping it will keep it lighter or show different color, then playing with the leaf while exposing it multiple times. It really almost darkens from white through yellow to red, then black. Some purples. This is still undeveloped. Tried some things with other but will leave these in a dark place, probably print them in inkjet print. Happy with the result though.

WhatsApp Image 2025-12-17 at 21.38.09.jpeg



slight mistake with the stem of the leaf, but who cares.. some lint of quick drying it with paper towel also.

Cheers
Jan.
 

Raghu Kuvempunagar

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Jan, wow! Absolutely stunning Lumen! If you plan to fix this print, you might want to read @NedL's posts on using a Thiocyanate bath before fixing. That's probably the best method to retain the colours which fixer will otherwise kill.
 
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Jan de Jong

Jan de Jong

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Just had a go with Cyano-Lumen on the same type of Agfa Multigrade. I have never done Cyano-lumen, and I have not read-up on it. Meanwhile found that with use of the UV-flashlight my experimentation is a lot faster. So can produce for the Lumen 2 colors on the paper 1 while dry, which is grey and 2) orange brown while wet ir slightly alkaline. (there my be more possible like green or purple some how) will have to do a bit more experiments perhaps find something.
In any case the blue would be possible with a cyano layer. Unfortunately that eats away most of the brown coloring (as in my previous post)
Here the result of 3 work-ups on the paper
1) layered exposure with dry paper (grey) 2= orange brown layer 3) cyano type layer added. black/blue layer.
Then washed in water, here just dried (except some water drops) lets see how it looks tomorrow.
WhatsApp Image 2025-12-27 at 22.16.25.jpeg



Hope it is useful for someone, tips for more colors on Lumen welcome also.


cheers
Jan.
 
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tezzasmall

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Jan, wow! Absolutely stunning Lumen! If you plan to fix this print, you might want to read @NedL's posts on using a Thiocyanate bath before fixing. That's probably the best method to retain the colours which fixer will otherwise kill.
And here's a link to NedL's post mentioned above :smile::


Terry S
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Raghu Kuvempunagar

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These links are more relevant IMHO:


 
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Jan de Jong

Jan de Jong

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Hello, thank you yes I found those links. I have found with the above print in post #15 that the cyanotype layer seems to take away most of the light sensitive part of the paper. ie after the washing of the cyanotype layer and exposing it to the intense UV flashlight there is hardly any discoloration. So (have to do some more experiments and leave in the sun for some days) that the lumen is pretty much stabilized without fixing through the cyanotype emulsion.
 
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Jan de Jong

Jan de Jong

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Some further evolution in the experimentation, I have now picked up Onionography. The fast action of the concentrated UV light from these flashlights allows to do experiments much faster and so iterate faster to new things. Using the same Agfa Multigrade photo paper and an onion I discover the Onion juice also has a nice effect dry photo paper. Just sharing for inspiration and further experimentation. Still Lumen only so not developed. I guess the sulfur in the Onion reacts with the silver under UV light
Format 10x15 cm Onion Slice about 5 mm thick exposure by tracing and staying a bit longer on the thicker parts, total time about 3 minutes.

WhatsApp Image 2026-01-06 at 21.12.42.jpeg
WhatsApp Image 2026-01-06 at 20.51.00.jpeg
WhatsApp Image 2026-01-06 at 20.35.50.jpeg
 

Raghu Kuvempunagar

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Nice work!

I discover the Onion juice also has a nice effect dry photo paper. Just sharing for inspiration and further experimentation. Still Lumen only so not developed. I guess the sulfur in the Onion reacts with the silver under UV light

What happens is onion juice being rich in sulphur compounds, nucleates the silver halides in the photographic paper, post which the paper prints-out more effectively under UV light.

When I was working on nucleation of photographic film in reversal processing, I did some experiments with nucleating photographic paper too. I gave a short rinse to the paper in weakly acidic Thiourea solution to nucleate the halides in the paper. After a short wash and drying, I made a Lumen contact print on the nucleated paper. Two effects could be noticed - 1) exposure time decreased significantly 2) printout was more reddish brown and the colour was mostly retained by the print after fixing.

The same idea works when Cysteine Hydrochloride is used in place of Thiourea but the result is dark brown. Cysteine Hydrochloride is less toxic than Thiourea. Weakly acidic Kala Namak should also function similarly, haven't tried that. Maybe onion juice and Kala Namak might like each other in printmaking just as they go well together in cooking. 😄

Here is a Lumen contact print using Thiourea nucleation. Paper is unbranded RC Grade 3.

IMG_0600.JPEG
 
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Jan de Jong

Jan de Jong

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The same idea works when Cysteine Hydrochloride is used in place of Thiourea but the result is dark brown. Cysteine Hydrochloride is less toxic than Thiourea. Weakly acidic Kala Namak should also function similarly, haven't tried that. Maybe onion juice and Kala Namak might like each other in printmaking just as they go well together in cooking. 😄

That is a nice print, I like the color, much like what you get with the FerroBlend almost. And yes the ideas come while cooking :smile:
I will have to make some onion juice and see how I can apply that. It seems to have some powerful effect, also want to see the result after fixing, which you have explored a bit already. Good to know.
 
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