Homebrew PCBs

Hi Jon,

     I understand your problem here, and have worked in "the green 
darkness".

     You mentioned that the film is a proper black and white (no pink) 
when it comes out of the developer, so we can eliminate base color, 
anti-hallation backings/dyes, and so on. 

     I seem to recall running across this sort of thing a couple of times 
over the past couple of decades (while doing things that materials 
weren't designed for), but no specific solution springs to mind. It's 
possible that the proprietary PRD fixer, assuming there was one, may have 
had a component that stopped the "pinkage". A documented formula would be 
useful.

     In the meantime, I have one test and three, wait, *four* suggestions:

     Scrape the back (non-photosensitive side) of the film to see if 
there's a backing, and if so, if that's where the pink color resides.

     1. Run an extended wash/rinse on the side of the film that holds the 
pink. It may eventually clear.

     2. Dip a piece of developed pink film in some vinegar. If it clears, 
you may need a final trip through a stop bath.

     3. If #2 does nothing, try an alkaline bath, like some baking soda 
in some water to see if it clears. Sodium carbonate would be better, but 
that's not a typical kitchen item.

     4. Oh, also, try doubling the time in the fixer, I have a fragmented 
memory about "pink" being a problem when Tmax films came out way back 
when. The Tmax fixer was very strong and conventional fixers required 
twice the time to clear.

     I'm just assuming that you haven't tried these yet. I'd appreciate 
hearing if any of this helps, it seems like you've been through a lot of 
discussion here without getting anywhere.

     -Gary




>First, this is black and white LITHO film, not color film.  Second, it has 
>NOT been exposed to any stray light, and I am using the recommended safe 
>light as per the Kodak spec sheet.
>
>It is VERY VERY subdued, so after getting adjusted to the light, I can 
>BARELY see what I am doing.
>
>This film is only about 8 years old.  I have been using Agfa film with no 
>problem for years, my batch is now 13 years old.
>
>I can clearly see the film develops fine, and only turns reddish-orange 
>when put in the fixer.
>
>Thanks,
>
>Jon