Re: lith film and pinholes

[mmorrill2@qwest.net]

I seem to remember something about air bubbles 
forming in the presence of acids in gelatine. 
The pinholes could possibly be forming in an acid 
hardening fixer or a stop bath. I use plain water 
to slow the developing and then place directly in 
the fix. I have noticed that the more contrast in 
the film the more likely that there will be pinholes. 
Presoaking the film in a water bath before developing 
could prevent the air bubbles from forming under the 
surface of the emulsion. When submerging silver photo 
paper in developer I have seen bubbles form. Where 
they come from I do not understand. Yet they stream 
to the top.  

The hypothesis of an exhausted developer sounds viable 
too. I don't get air bubbles with very diluted developer 
but, then, exhausted developer has had its chemical 
composition changed through use. humm... 

These are just clues, for what it is worth.

Mark A. Morrill
Gummist since 1988