Quote Originally Posted by Francesco
Well done Sandy.

1. In this article you recommed a presoak in distilled water of 5 min. in BTZS tubes. In another you recommended 2 to 3 mins. Any real difference? (BTW, I place the distilled water in the tube caps and then shake it well for about 2 or 3 mins).

2. You recommed the use of a stop bath in the article. How long time should the film stay in the bath? You have also stated elsewhere that 1 minute in water was good enough if the fixer used is TF-4. Is this still the case? (By the way, I put the stop bath in extra BTZS tube caps and agitate slightly for about 30 seconds before I let the film lie in plain water for 1 minute. What do you think?).


I use a five minute pre-soak time because it adds to consistency of results when testing various films, especialy with short development times. Rate of develoment depends on induction and transfer of chemicals into and out of the gelatin emulsion, and the rate varies among films. At five minutes they all perform about the same. For any given film a 2-3 minutes pre-soak should be fine.

About the stop bath, when using a diluted acetic acid bath the film only needs to stay in the bath for 10-15 seconds. If using water, change the water 4-5 times over a period of about a minute.