[Leica] Re: freshness (was Mark Rabiner's)

["Eric" <ericm@pobox.com>]

Rei:

>slightly tangential, but what tests (if any) do people use to check
>freshness of their chemistry?

Why, develop another 4 rolls, of course.  :)

Over Christmas, I managed to get behind by 12 rolls.  I labelled each as I
finished, so I'd have a rough idea what was on each roll.  When it came time
to develop, I mixed and matched so that if any one batch were a total
disaster, I wouldn't screw up all the similar pictures...I'd have some
backups.  Usually, I don't have more than 4 rolls, so I just load 'em and
go.

>with fixer, poeple drop in a film leader and measure time to clear and
>then fix for 3 times that amount.  but how clear is clear?  i've had old
>fixer that left the film base about .10 denser than the same film with
>fresh fixer.  (i refixed and the film was fine).

According to the Book of Mark, verse 1:3, Kodak rapid fixer is good for 3
months once mixed up.  A half gallon is good for 20 archival rolls according
to Kodak.  I use two fixes, and rotate them monthly so any given half gallon
is tossed after 2 month's time.  Then, I don't have to worry about their
going bad.  If I run more than 20 rolls in a month, then I rotate earlier.
The first time in a month that I run film, I toss out fix #1.  Fix #2
becomes fix #1.  Mix up a new batch and it becomes fix #2.  Film goes into
each fix for 5 minutes with a water bath in between.  Which is about 5x time
to clear for new fix.


Eric
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