HIPPOLYTE BAYARD direct positive process

Discussion in 'Alternative Processes' started by brucej, Feb 16, 2009.

  1. brucej

    brucej Member

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    Has anybody tired this ?

    The direct positive process involved exposing silver chloride paper to light, which turned the paper completely black.
    It was then soaked in potassium iodide before being exposed in a camera.

    After the exposure, it was washed in a bath of (Sodium thiosulfate) hyposulfite of soda and dried.

    The resulting image was a unique photograph that could not be reproduced.

    Due to the paper's poor light sensitivity, an exposure of approximately twelve minutes was required. Using this method of photography, still subject matter, such as buildings, were favored. When used for photographing people, sitters were told to close their eyes so as to eliminate the eerie, "dead" quality produced due to blinking and moving one's eyes during such a long exposure.
     
  2. phritz phantom

    phritz phantom Member

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    sounds interesting.
    is the paper still wet (from the iodide) during exposure?
     
  3. Ian Grant

    Ian Grant Subscriber

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    Kodak manufactured a direct copying film that worked in a similar way, and I think EFKE still make a direct positive paper which is sold by Freesyle. They still need developing though.

    Ian
     
  4. brucej

    brucej Member

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    sorry I dont have have that info
    do you think it should be wet ?
     
  5. phritz phantom

    phritz phantom Member

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    i have no idea... this is the first time, i've heard about that process.
    if you'd soak it in iodine, it gets wet, which would be rather impractical to have inside the camera. but i don't know if the process allows a intermediate drying.
     
  6. jnanian

    jnanian Advertiser Advertiser

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    "professional duplicating film" was a single step ( negative to negative or positive to positive ) film that kodak sold but stopped making.
    photowarehouse sells the same thing .. it is very slow, like azo paper,
    and requires a floodlight to expose (i have used a 300W bulb) it would be between 7 and 10 stops slower than conventional photo paper, rated somewhere
    between asa 6 and 25 ... and it is processed in paper developer ...

    some folks have had very good results shooting the efke paper.
    on the large format forum there are a handful of recent posts that look very nice.
     
  7. GCyberfish

    GCyberfish Member

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    I tried this with standard photo paper and got ... intresting results but nothing useable for
    photographic purposes:
    [​IMG]

    I may have to experiment with the time of preexposure and the type of
    Developer. Maybe a ...surface -developer?(<-don´t know the word for it) would work better than RODINAL.
    TALBOT described the Iodide-method in combination with his calotype
    process.

    I hope you can understand my english :smile:
     
    Last edited by a moderator: Feb 21, 2009
  8. Eugen Mezei

    Eugen Mezei Member

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    An advantage of the process was that the papers could be prepared before use and stored up to one month. So I guess they were dry.

    Still I am very interested to get this information confirmed (or infirmed) as I would like to try the process if the paper is indeed dry when I put it into the sheet holders.

    Did any one of you tried the process in practice? (Bayards one, please no further references to what more or less similar can be obtained on the market. I am interested in this as a method to prepare my own photosensitive material.)
    I think it could be very usefull for static models (arhitecture, maybe nature too). Bayard reached 12 minutes for an exposure, that is not too bad.

    Greetings,
    Eugen
     
  9. c6h6o3

    c6h6o3 Member

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    The paper has to be exposed wet. The process only works in the presence of light, oxygen and water.
     
  10. cliveh

    cliveh Subscriber

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    Like most halogen based processes they work faster when wet, but will still work when dry, but at a slower rate.