Dennis
Hello!
I lost four films yesterday during the reversal process
:-(
I followed the process described in the thread "Kehret Um"
[phototec.de].
Initial developer: Neutol NE 1+7
Bleach: 8% KMNO₄ and 4% H₂SO₄ 1+1
(i.e. 4% KMNO4 and 2% H2SO4 in the final Bleach bath)
Film: PO100c 35mm
The Bleach bath came out of the bottle completely brown, which didn’t worry me at first
because it was sometimes still rather violet, and other
times already quite brown after a 7-minute Bleach time.
I had previously extended the bleaching time from 5 to 7 minutes
because (rarely) ‘negative highlights’ appeared on the finished
slides; after 7 minutes of bleaching, everything was usually
fine.
When I re-exposed the films, I discovered stronger
traces of blackening. Huh? But – weren’t they supposed to be negative?
Help! That’s when I had the idea to bleach them again.
Unfortunately, the stock solution of potassium permanganate had, of course, just
run out, and I first had to quickly weigh out new KMNO₄,
prepare it, filter it… naturally, I lost a lot of time in the process.
In the end, the four PO100c films perished due to the long processing time,
the emulsion completely swollen, detached and shrivelled,
despite the Geladur protectants in the water and solutions. :-(
Fortunately, most of the photos can be re-shot.
But I’m really annoyed about the time wasted
(three whole days of shooting at an artists’ colony in Mecklenburg-
Vorpommern >Schloss Broellin< and one day to develop.)
Now I’d like to ask you:
1. I always prepare potassium permanganate and diluted sulphuric acid for four
developing runs and then sometimes store these solutions
for two or three months in glass bottles, separately of course!
Does this storage already damage the dissolved KMNO₄?
(The sulphuric acid really shouldn’t ‘mind’ this)
(Of course, I only mix the solutions together for a few minutes
)
2. If I have fresh doubts about the effectiveness
of the Bleach bath, does it make sense to immediately carry out a second Bleach bath cycle with fresh
Bleach bath?
3. Might it help as a preventative measure to increase the concentration of the Bleach bath?
Best regards
Dennis
