Why photo silver not reusable but photochromatic silver is

Discussion in 'Alternative Processes' started by Mustafa Umut Sarac, Nov 17, 2010.

  1. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

    Messages:
    4,571
    Joined:
    Oct 29, 2006
    Location:
    İstanbul
    Shooter:
    35mm RF
    I am not good with chemistry but I want to ask that why photochromatic glasses which uses silver crystals are reusable but photographic silver is not ?

    Is reason that we want to fix the image ?

    If we can reuse the silver as photochromatic glasses without developing it , it opens a entire world to read it with most basic electronics !

    Awaiting your reply ,

    Best ,

    Mustafa Umut Sarac

    Istanbul
     
  2. Vlad Soare

    Vlad Soare Member

    Messages:
    253
    Joined:
    Jan 16, 2009
    Location:
    Bucharest, R
    Shooter:
    8x10 Format
    It is possible to "erase" an unfixed photographic image and to replace it with a new one. Use a bleach bath. The developed silver will revert to silver halide.
    I suppose you could let the material dry and then record a new image if you wanted to. :smile:
     
  3. Galah

    Galah Member

    Messages:
    481
    Joined:
    Feb 4, 2009
    Location:
    Oz
    Shooter:
    Multi Format
    I'm not sure what your question is, but -in the process of developing negatives and prints- there is much unused silver in solution as silver salts. In commercial labs, this silver is routinely recovered from the otherwise "waste" liquids by the process of exposing these liquids to iron wool. The iron displaces the silver in the solution causing the iron wool to be replaced by metallic silver, which is thereby once again made available for re-use. :smile:

    In a commercial lab, the quantities over a year are significant. :smile:
     
  4. AgX

    AgX Member

    Messages:
    11,592
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    Good question Umut,

    The basic process in convential photographic silver halid and photochromic silver halid systems is the same.
    But do not overlook the different matrices employed.

    And a photochromic silver halid systems has inded been used in photographic image forming.
    I hinted at the latter already at another thread of yours.
     
  5. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

    Messages:
    4,571
    Joined:
    Oct 29, 2006
    Location:
    İstanbul
    Shooter:
    35mm RF
    Vlad ,
    Really funny , isnt it ?
    Galah ,
    You saw the concept from another view , thats why I love APUG.
    AgX,
    You always understand whatever I am talking about.

    Suppose , you made a photochromic plate from electric conducting plastic.
    Than you take a big LCD display , remove the liquid crystal and put each electronic patterned transistor covered transparent plates to the each side of the photochromic plate.

    You attached this hybrid matrix to the Large Format camera , took a picture and two aligned transparent electronic plates scanned the photochromic plastic and read the resistivity.

    You get digital image from chemical film .

    When you go to the home , take another LCD and contact print to the paper

    I have many many ideas similar to this.

    One of them is to read the transparent electric conducting photochromic film with electronic chirp applied scanner linear array. Not transistors but a antenna like rod which reads the plate like a radio receiver

    Umut
     
  6. AgX

    AgX Member

    Messages:
    11,592
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    An electroconductive plastic does not necessarily show photochromism.
    You mean photoconductivity resp. photoresistance.

    But I wouldn't call that film a chemical film.
     
  7. Mustafa Umut Sarac

    Mustafa Umut Sarac Member

    Messages:
    4,571
    Joined:
    Oct 29, 2006
    Location:
    İstanbul
    Shooter:
    35mm RF
    of course. you have to mix silver crystals in to electroconducting plastic and cast a plate.
    Than crystals will change with light , just like liquid crystal in lcd monitor.

    As we change the electric field to read lcd monitor at homes
    conducting photochromic plate will change the electric field as it sees the light.

    So resistivity is the key factor , I guess.
     
  8. AgX

    AgX Member

    Messages:
    11,592
    Joined:
    Apr 5, 2007
    Location:
    Germany
    Shooter:
    Multi Format
    Still the term photochromic is erroneous here, as it means a reversible change in spectral transmission under influence of light.