Switch to English Language Passer en langue française Omschakelen naar Nederlandse Taal Wechseln Sie zu deutschen Sprache Passa alla lingua italiana
Members: 70,907   Posts: 1,555,900   Online: 1060
      
Results 1 to 8 of 8
  1. #1
    Joe VanCleave's Avatar
    Join Date
    Jan 2004
    Location
    Albuquerque, New Mexico, USA
    Shooter
    Pinhole
    Posts
    484

    Electrophotography (Xerography)

    Just finished reading a biography of Chester Carlson, the inventor of Xerography, also known as Electro-photography (and not to be confused with Kurlian Photography).

    I was curious whether anyone else has considered recreating his early experiments, to wit:

    His initial experiments, done at home, involved a sulfur-coated zinc plate, electrostatically charged using a fur mitten. It was then exposed to a light pattern, then a special powder was sprinkled onto the plate, and the excess blown off. The remaining powder adhered to the plate in the negative pattern of the light image previously exposed to the plate (the sulfur layer acted to be slightly conductive upon exposure to light, discharging the electrostatic field only where light struck the plate). Since his powder did not have the properties of modern-day Xerox toner, he transfered the image to a sheet of wax paper by pressure, then heated the wax paper over a hot plate to fuse the image.

    Later experiments, leading to the "Ox box" manual Xerographic machine in the early 1950's by Haloid (the forerunner of Xerox Inc.), used amorphous selenium coated plates, which are much more light sensitive than sulfur is.

    Does anyone have any practical ideas on how to proceed with a home/darkroom recreation of this experiment? Obviously, it's fairly easy to get bottles of toner. Haloid's later experiments used a magnetic brush, composed of a mixture of iron filings with toner on a magnetic wand, to swipe across the charged plate; the toner stuck to the image charge on the plate, while the iron filing adhered to the magnet. This should be fairly easy to make.

    As I see it, the hard part is getting the selenium plate. Charging the plate could be via a small electrostatic generator, if rubbing fur by hand is insufficient.

    What I would like to see is an in-camera method of exposing the charged plate via a LF lens, then process the toner image onto fine art paper.

    Any suggestions are welcome (other than ... 'just use a copier'...).

    Joe

  2. #2
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    I though of doing this awhile ago, but dismissed it as rediculous. It's good to know that I'm not insane :-).

    But that's a GREAT idea.

    Sure, using a copier would be easy, but where's the fun and adventure in that?

    You're (obviously) all set on the toner; that's available easily.

    But I wonder if the contast would be acceptable for in-camera use?

    I wonder if the sulfur plate would be easier to start out with? Sulfur is significantly easier to get than selenium, and probably cheaper.

    Hmm

    this has me thinking, I'm going to devise something in my head here; I'll get back to you when I do :-D

  3. #3
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,183
    Images
    65
    Xerography can be done at most any contrast as long as the V LogE curve is adjusted accordingly. (V = Voltage and Log E is log Exposure) This makes curve shape adjustments in a manner similar to DLogE in film and paper.

    It can be done in color as well using colored toners. If you wish prints, the material to use is Titanium Dioxide. It, coated on conductive film makes a good reflection print material.

    I have seen superb B&W and Color prints done this way.

    PE

  4. #4
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    Interesting to know that it's been done before!

    PE, do you have any suggestions as to how to go about this?

  5. #5
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,183
    Images
    65
    Quote Originally Posted by htmlguru4242 View Post
    Interesting to know that it's been done before!

    PE, do you have any suggestions as to how to go about this?
    I have no idea. Sorry. I've seen it done at EK. It was called, internally, Electrocolor. There was quite a development project on this material in the 70s. I wish I could tell you more, but I only saw it done.

    PE

  6. #6
    htmlguru4242's Avatar
    Join Date
    Aug 2005
    Location
    Sandy Hook, CT
    Shooter
    Multi Format
    Posts
    973
    I see. That's still neat though.

    What about your mention of Titanium Dioxide?

  7. #7
    Photo Engineer's Avatar
    Join Date
    Apr 2005
    Location
    Rochester, NY
    Shooter
    Multi Format
    Posts
    23,183
    Images
    65
    Titanium Dioxide was coated on film or RC support. It is or can be made, light sensitive with appropriate sensitizers and can be used in the Xerographic process. Light plus a charge will deposit the dye or toner in the TiO2 leaving an image.

    The images I saw compared well with the Ektacolor Paper prints I saw by comparison in the 70s.

    PE

  8. #8

    Join Date
    Sep 2002
    Location
    Tijeras, NM
    Shooter
    Medium Format
    Posts
    1,246
    I have though about this is an interesting way to do digital... you would expose an electrostacilly charged plate, run it through some 'combs' and digitize the measured voltages.
    art is about managing compromise



 

APUG PARTNERS EQUALLY FUNDING OUR COMMUNITY:



Contact Us  |  Support Us!  |  Advertise  |  Site Terms  |  Archive  —   Search  |  Mobile Device Access  |  RSS  |  Facebook  |  Linkedin