Results 1 to 5 of 5

Thread: Desensitizing Film?

  1. #1

    Join Date
    Nov 2006
    Location
    Sacramento, CA
    Posts
    64

    Desensitizing Film?

    I came across the following in a book dated 1948:

    "Desensitize the plates by one minute's immersion in 1:2000 Pinacryptol yellow. Alternatively proceed in darkness"

    It then goes on describe tray processing of the plates.

    I took this to mean I can desensitize film and process in daylight, or not desensitize and process in darkness. Otherwise, why would I desensitize the film if I have to process in darkness anyway. Am I reading this correctly? What is Pinacryptol yellow? Does it mean to process in blue light and the Pinacryptol yellow blocks it?

    Eric.

  2. #2

    Join Date
    May 2006
    Posts
    2,588

    Re: Desensitizing Film?

    You can desensitize film to develop by inspection, so your interpretation may be correct - if you desensitize you can proceed UNDER SAFELIGHT (not daylight).

    Pinacryptol Yellow acts as both an anti-fogging agent (restrainer) and a desensitizer. It makes the film not sensitive to red-yellow.

    You can also use Pinkryptol Green, which makes the film insensitive to green - and so you'd need green safelight.

  3. #3

    Join Date
    Nov 2006
    Location
    Sacramento, CA
    Posts
    64

    Re: Desensitizing Film?

    Thanks. I just read the instructions for Amidol at the Photographers Formulary site, where it's stated that this dye can be used for DBI under a 40-60 watt series 3 wratten safelight. That's quite bright. I wonder how much time the film can be exposed to such light. The instructions read 1:200 rather than 1:2000.

  4. #4

    Join Date
    Aug 2004
    Location
    New Hampshire
    Posts
    482

    Re: Desensitizing Film?

    Whoooa....

    Proceed under a dim safelight ... perhaps safer yet, proceed in darkness till you are near the point where you really need to see the film to see the results. A dim safelight, very dim is quite usable. There's a good article on developing by inspection at: www.michaelandpaula.com/mp/devinsp.html which is a bit more liberal about safelighting during DBI.

    C

  5. #5

    Join Date
    Oct 2004
    Location
    S.W. Wyoming
    Posts
    1,137

    Re: Desensitizing Film?

    The data I have from 1943 says to not use the green kind for panchromatic film. It doesn't say why. It seems after desensitizing, you can develop by inspection under your normal safelight for brief periods. The light must be no closer than 4 feet to the film. 60 watts ??? That sounds like development to destruction to me.

Similar Threads

  1. Some observations on old Kodak 4x5 pack film
    By Chauncey Walden in forum Darkroom: Film, Processing & Printing
    Replies: 21
    Last Post: 17-Dec-2018, 19:01
  2. How capital ($) intensive to make color film?
    By bglick in forum Darkroom: Film, Processing & Printing
    Replies: 25
    Last Post: 18-Jan-2006, 14:28
  3. film is gone
    By robc in forum Darkroom: Film, Processing & Printing
    Replies: 40
    Last Post: 17-Jan-2006, 19:32
  4. film loading/unloading
    By Barret in forum Darkroom: Film, Processing & Printing
    Replies: 7
    Last Post: 2-Aug-2004, 12:24
  5. Choosing a large format film medium
    By Rory_3532 in forum Darkroom: Film, Processing & Printing
    Replies: 14
    Last Post: 10-Oct-2003, 19:40

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •