Ultraviolet Film?

Discussion in 'B&W: Film, Paper, Chemistry' started by Michel Hardy-Vallée, Sep 21, 2005.

  1. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council Council

    Messages:
    4,350
    Joined:
    Apr 2, 2005
    Location:
    Montréal (QC
    Shooter:
    Multi Format
    Ok, this is a bit of a whimsy question, but why is it that there are no
    specifically UV-sensitive films on the market, despite the presence of films with IR sensitivity? I presume that the scientific world might use such films, if they exist, but wouldn't it be neat to take a picture using only the UV rays?

    Of course, the fact that I don't find such films must mean that there's a good reason I am not aware of like a good young imbecile...
     
  2. htmlguru4242

    htmlguru4242 Member

    Messages:
    973
    Joined:
    Aug 9, 2005
    Location:
    Sandy Hook,
    Shooter:
    Multi Format
    I don't believe there are many UV only films. The main reason for this is that nearly all photographic materials are already sensitive to ultraviolet light. With standard black and white film, and a UV - pass filter (which is a deep, deep purple, and passes only UV light), you can take pictures in just the Ultraviolet wavelengths. The main problem with this is that glass lenses do not pass UV terribly well. New coated lenses block even more of this UV light, making UV photography difficult, though not impossible.
     
  3. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,900
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    All films are UV sensitive. A raw emulsion with no other work being done to it has maximum sensitivity in the UV region. Pure chloride emulsions are, for all practical purposes, sensitive only in the UV region.

    Lenses are not transparent to UV. You must get quartz lenses (costing one arm and leg per lens minimum)

    Many films have UV overcoats to preclude UV exposure anyhow, so you would have to get one with no UV filter layer, or you would have to buy a special UV film. The do exist.

    They are used in medical, forensic and other scientific applications where detection of UV is critical.

    PE
     
  4. John_Brewer

    John_Brewer Member

    Messages:
    454
    Joined:
    Apr 25, 2004
    Location:
    Bristol, UK
    Shooter:
    8x10 Format
    I think that you use 'normal' film. Kodak certainly did have a paper on UV photography, ten years ago, I had a copy. UV light makes certain things fluoresce ie emit electromagnetic radiation which can be photographed using regular film. By eliminating normal light and using black light tubes you will get the best result. Some things including certain rocks give a completely different colour than under natural light others like some fungi (the ringworm fungus is one) just glow a violet colour. Fluorescing agents are added to many products like washing powder/liquid and paper so they seem "whiter than white" ( to quote the Daz ads in the UK) under strong sources of UV eg sunlight.
     
  5. KenS

    KenS Member

    Messages:
    379
    Joined:
    Jan 2, 2005
    Shooter:
    Multi Format
    Hi John,

    You do not need anything special in the way of lenses to record UV fluorescence from subjects... any glass lens will so do.

    However, if you need to record the relected UV (or IR) you will need something similar to the Hasselblad 150mm UV Sonnar or the 85mm Pentax Ultra Takumar with the visible-light cut-off filter. My Ultra Takumar is the one with only fluorite and quartz elements... no "glass" per se. The Ultra Takumar will record photographic images from "about" 250 to 1250nm., but you do need bellows for images less than about 3 feet.

    Ken
     
  6. htmlguru4242

    htmlguru4242 Member

    Messages:
    973
    Joined:
    Aug 9, 2005
    Location:
    Sandy Hook,
    Shooter:
    Multi Format
    I believe that i've heard that Kodak T-Max 100 for B&W work, and fuji RPT (don't remember which one) is good for color UV work (the layers in some color films will render some UV in red, blue, violet and some white.

    Also interesting, and allowing you to bypass the lens transmission issure is UV pinhole photography. Placing a UV filter in front of the pinhole will let you record images in UV. Although I have not tried this myself, I've seen it work.

    The results of UV photography, either in color or B&W are quite striking.
     
  7. Photo Engineer

    Photo Engineer Subscriber

    Messages:
    25,900
    Joined:
    Apr 19, 2005
    Location:
    Rochester, NY
    Shooter:
    Multi Format
    There is a Scandinavian web site that I'll try to look up. It has a lot of UV and IR photography there in both conventional and digital.

    I suggest Kodak publication M3, "Infrared and Ultraviolet Photography, if it is still available. In this book, Kodak endorses the reflected fluorescent method rather than using direct UV photography, but they list other resource material that describes both methods.

    PE
     
  8. eumenius

    eumenius Member

    Messages:
    768
    Joined:
    Jan 6, 2005
    Location:
    Moscow, Russ
    Shooter:
    Medium Format
    Yes, as many people here have mentioned already, every B/W material is able to record UV image. The main problem in that case is own fluorescence of some organic compounds and especially film base in UV, what can give overall flare, halo, and ruin the contrast of the image. To record the shortest UV (we had such a need in our lab once), I remember we had to coat the regular non-sensitized photo plate with some kind of synthetic mineral oil, giving a strong visible excitation fluorescence at 205-215 nm wavelength, or close to. That was a kind of sensibilisation, done in a view camera :smile:

    Cheers,
    Zhenya
     
  9. Michel Hardy-Vallée

    Michel Hardy-Vallée Membership Council Council

    Messages:
    4,350
    Joined:
    Apr 2, 2005
    Location:
    Montréal (QC
    Shooter:
    Multi Format
  10. glbeas

    glbeas Member

    Messages:
    3,307
    Joined:
    Sep 25, 2002
    Location:
    Roswell, Ga.
    Shooter:
    Multi Format
    I once read an article that stated for the highest UV sensitivity or acutance, don't remember which, they etched the emulsion down to leave the silver halide crystals exposed. No mention was made as to how this was accomplished.
     
  11. nworth

    nworth Subscriber

    Messages:
    2,192
    Joined:
    Aug 27, 2005
    Location:
    Los Alamos,
    Shooter:
    Multi Format
    AFAIK, all films are sensitive to the near ultraviolet. The sensitivity falls off at shorter wavelengths, mostly because gelatine absobs UV. Special UV emulsions used to be available for spectrographic use in the far UV. Ilford may still make them, but possibly only on special order. Some investigators made there own. (Look up Lippmann emulsions.) Very thin emulsions are needed in the far UV.

    As far as camera use is concerned, lenses absorb most UV except the longest wavelengths. There are also focussing problems, since common lenses are designed and calibrated only for visible light.