• Ultraviolet Photography

Ultraviolet film photography

5 replies to this topic

#1 Hornblende


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Posted 07 August 2018 - 18:12

Hello folks,
I've been experimenting with digital UV photography for a while now.. I want to try something else :D. I recently got two nice film cameras: an Olympus OM4-Ti (35mm) and a Rolleiflex SL66 (medium format) and I would like to try shooting in UV with them.
Several questions arise:

- How sensitive to UV is black and white film compared to a digital sensor?
- Does the film emulsion type influence the UV sensibility (T-grain vs traditional grain)?
- Is there a particular brand of B&W film that is better than the others?
- I there a particular ISO rating that works better?
- What about color negative films?

Thank you for your time.

#2 enricosavazzi


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Posted 08 August 2018 - 07:54

Silver halide sensitivity to UV should be much higher than the UV sensitivity of solid-state sensors. In addition, silver halide sensitivity increases with decreasing wavelength, so with film in principle one can record UV-B and probably the longer wavelengths of UV-C (shorter wavelengths are absorbed by oxygen in the atmosphere, so this becomes the limiting factor for ambient-light UV photography, together with the availability of suitable lenses).

The practical problem is however that the organic material in the film gelatin absorbs UV, and probably many BW films also have UV-absorbing chemicals in the gelatin or in a protective layer above the gelatin. While high-sensitivity films contain the most silver halide, in practice their thick gelatin may be a problem, and thinner, lower-sensitivity emulsions may actually perform better.

There should be some members who do or have done UV imaging with silver halide films. I will leave it to them to propose specific film types.

Edited by enricosavazzi, 08 August 2018 - 07:55.

-- Enrico Savazzi

#3 Adrian


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Posted 08 August 2018 - 09:06

I completed a Masters thesis in 1994 on Insect vision using UV photography. I even managed some crude multispectral sets (either projecting three images on top of each other, or using the new fangled Photoshop!). I made my own grey scales by mixing Magnesium Oxide and Carbon Black in various proportions, together with liquid collodion.

I used either Ilford FP4, rated at 200 ISO, or Kodak Tri-x rated at 400 or 800 ISO, processed in ID-11 developer at 1:3 for finest grain. I did not have access to quartz lenses, so used standard Nikon lenses, and multi-flash techniques (some images were exposed for 32 flashes!). Reciprocity failure was a ,major problem. The Broncolor flash heads used had removable quartz hoods to increase UV output.

I don't think chromogenic emulsions were around at the time.

I also don't think that colour negative emulsions would be any use - I would image that the integral orange mask would filter out any UV.

I have been thinking for some time of comparing B/W emulsions with digital sensors, but haven't got around to it, so would be very interested in your results. I will see if I can find some of my old negatives and scan them to put up here.

#4 Adrian


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Posted 08 August 2018 - 11:22

I have found some images from 1994, of the pitcher plant Sarracenia purpurea.
Technical details: 105mm micro-Nikkor @ f/11. 2 x BronColor flash heads with UV domes removed; 12 x flashes. Film: Ilford FP4 rated at 200 ISO. Filter: Kodak 18A Wood’s Glass (no problem with IR leakage with film!)

Looking back, not bad quality!

Attached Images

  • Attached Image: analogue UV.jpg

#5 OlDoinyo


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Posted 08 August 2018 - 15:42

I have actually posted a few film images here...

B&W film is much more sensitive to UV than digital sensorsand that sensitivity in theory extends below 300 nm. I have achieved a working ISO of around 10 with 100-speed film and around 50 with Ilford Delta 3200, the latter allowing hand-held shooting and photography of moving subjects. Color negative film seems to work OK but the UV image will be composed almost entirely of yellow dye. It is possible to mix UV photography with ordinary photography on the same roll by changing filters. Avoid color slide film, as most are overcoated to suppress UV response (an exception was Kodak Aerochrome, with a working ISO around 30.) Film UV images are fairly monochromatic, and even with color film any residual chromaticity will be mostly due to visible contamination. IR contamination is no issue for most films because they are incapable of recording IR.

There will be less difference between the effective speeds of nominally slow and fast films in UV compared to visible preformance, because the faster films rely on sensitizers which are optimized for visible rather than UV.

It is difficult to say if the Rolleiflex's lens will be a good UV performer; that of the similar Minolta Autocord is adequate but not outstanding in this regard. You can perform a pinhole bandpass test on it if you wish.

Edited by OlDoinyo, 08 August 2018 - 16:14.

#6 Hornblende


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Posted 09 August 2018 - 17:59

Thank you all for your response :)
I see this is a complicated subject... I'll first test my lenses with the pinhole methode, and do some test with the Ilford Delta 3200.