Electric CAMERA Works Without Film (Jun, 1932)

This seems very similar to a xerox machine.

Electric CAMERA Works Without Film

SELENIUM, that wonderful metal that changes its electrical resistance upon exposure to light, has recently been used in a most revolutionary camera developed by Mr. K. Wilcke, German scientist. In the ordinary sense of the term, this experimenter uses no film, and entirely dispenses with the use of silver compounds.

In a special camera, shown above, the light enters through a standard lens and strikes a glass plate, on which is a very fine film of metal-like platinum or gold; so fine that it will permit the passage of light. Backed up to this metal film is a layer of selenium, behind which is placed a piece of paper soaked in a special electrolyte. The last member of the group is another metal plate, which serves as second electrode.

Due to the process of electrolysis, the image impressed upon the selenium will be reproduced upon the paper, the most metal being deposited in the dark portions of the picture.

11 comments
  1. carlm says: April 1, 20103:32 am

    Xerography (Dry writing) transfers a dry plastic powder (Toner) through a static electric charge onto a piece of paper. The powder sticks at the points where light doesn’t strike a selenium coated roller. The powder is then fused to the paper when it goes through a heated roller. This camera uses a liquid electrolyte that transfers metallic ions to the paper. Quite different.
    I should take that test to see if I’m a bore.

  2. Casandro says: April 1, 201010:08 am

    It’s certainly not xerographics.

  3. KD5ZS says: April 1, 201010:43 am

    Interesting because Selenium is a semi-conductor and was used to make rectifiers prior to silicon being adopted– so how come no selenium transistors, charge coupled devices or Light emitting diodes?

  4. Don says: April 1, 201012:32 pm

    silicon certainly superior semiconductor, see?

  5. Jari says: April 1, 201012:59 pm

    KD5ZS: What comes to my mind, is that when bipolar transistor was invented, Germanium was already used in diodes and was a better semiconductor. For CCD’s, Selenium was used in exposure meters at a time, but the Selenium cell itself is huge. For LED’s, they seem to need quite “esoteric” elements to work.

  6. KD5ZS says: April 1, 20101:18 pm

    LED’s need Gallium and Arsenic to work. The old selenium rectifiers were not very efficient. I think another light sensitive material was Cadmium Sulfide (CdS). I don’t recall if they if they were used as a light sensitive resistor or not.

  7. DrewE says: April 1, 20102:03 pm

    CdS photoresistors were (and still are) quite common. They’re very slow responding in comparison to many other modern photodetectors, but are frequrently used in applications where response speed isn’t a great concern (such as automatic controls for streetlights or nightlights).

  8. jayessell says: April 2, 201011:24 am

    Is the photoelectric surface sensitive ONLY when current is applied?

    Is the image printed to paper DURING or AFTER exposure?

    PS:

    I’m pleased that none of the regulars here made any rude comments about the
    person being photographed.

  9. Toronto says: April 4, 20108:17 pm

    I have light meters in both Selenium and CdS. The Selenium one has a cell that’s approximately 1cm high by 4cm wide – quite large. It’s branded as a Voigtlander (the camera company) and is from about 1954.

  10. Jari says: April 10, 20101:30 pm

    Toronto: Me too. No Voigtlanders, though. I have one Gossen (IIRC) which have a separate ~4x4cm booster cell. It is possibly a Gossen, but it’s stored, so I can’t check it. I really need to catalog all the accessories as well….

  11. Richard says: August 16, 20101:49 am

    The underlying process sounds like a variation on Bains’ “chemical telegraph” idea – which is a very old one.

    http://distantwriting.c…

    It also sounds like the sort of thing a modern-day hacker could have a lot of fun with…

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