Extending Fix Times
It occurred to that as more and more films are put through
some developers the development times are increased. Is it
a common practice to do the same amoung those that slowly
exhaust a fixer with ever more through put? Dan
Just the normal 2x the clearing time. When the original time has doubled then I make more from fixer scratch. I have been using quite a bit of Imagelink HQ. In regular, not rapid fixer, it clears within seconds. I develop my film in the dark with 4 tanks that each have their own chemical and the reels on a lifting rod. I have yet to pull the film from the fixer without it being completely cleared.
Claire (Ms Anne Thrope is in the darkroom)
I goofed my first post. I had in mind prints and I suppose
Originally Posted by Claire Senft
FB at that. I'm reminded of Ilford's archival sequence of
some years ago. One minute in film strength fixer,
from first through forty. Dan
There is a simple test for determining fix time visually for paper. I'll leave it to the student to figure it out.
OK PE, I'll bite...
Here's what I do to determine clearing time for papers.
Under safelight, I immerse a test strip of paper in the fixer in stages. The strip is marked in "inches" with a Sharpie. 20-second intervals are close enough for me. The first "inch" gets 20 seconds, then the second "inch" is immersed and so on. After I've done this to a total of a few minutes, I rinse, turn on the white light and toss the strip into the print developer.
The strip that is completely paper-base white with the least fixing time is the clearing time for the paper.
Easier done than said...
And, while I'm at it dancqu... I used to determine clearing time for each batch of negatives with a clearing test and adjust fixing time accordingly (i.e. three times the clearing time). Now, however, I use two-bath fixing for negatives and prints, and though I still use clip tests to determine exhaustion of the first bath, I no longer extend fixing time. That is one of the advantages of the two-bath method.
I do use dilute fix one-shot every now and then for the occasions when I only have a very few negatives to develop at one time, but mostly develop now in larger batches (40+ sheets), which lends itself better to the two-bath method.
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IMHO only the Tmaxes require longer fix time.
I normally test the clearing time of film every ~6-7 rolls and then dump the fixer or adjust the time.
Mama took my APX away.....
There are 3 tests Doremus, and you nailed just about the hardest.
The other two can be done without any washing needed, and one sacrifices about 1 ml of fix.
I thought Dan, being an expert, would have all 3 by now.
Well, can someone indulge those of us who aren't "experts"?
Originally Posted by Photo Engineer
They give us those nice bright colors
They give us the greens of summers
Makes you think all the world's a sunny day, oh yeah.
I don't think, when I had my darkroom, I ever totally exhausted fixer, I always did film as one shot, for both develop and fix, because it left me with the most consistent results. Figured the slightly higher process cost was cheaper then ruining negatives, and having to try and repeat a shoot.
Originally Posted by dancqu
For paper I would mix up a batch, and when the session was over, I would toss it, even printing all day, I don't think I ever exhausted fixer. You should probably read the directions for the fixer, as it should tell you the capacity. The spec sheet for Ilford Rapid fixer has capacities on it, you can get the spec sheet from the Ilford website. Kodak probably has the same info on their website for their fixers.
Then again I have to admit, I had a pretty low volume operation....
Our high school darkroom did it this way, there was a label on the shelf by the developer bottle, every time you did a roll, you marked it on the label. Every 10 rolls you tossed the developer, stop and fix and mixed up fresh. The capacity of the fixer and stop were more then the developer, this worked well for a lab that might see 40 rolls on a single day..... Beside the label was a chart of time based on the number of rolls..... I often did my processing at home though, because there was usually a lineup at school. IIRC they had a machine for print processing (it was 28 years ago now), so unless it was a weekend and I wanted my results for Monday, I printed at school.
I don't test for the amount of time needed to clear. I test for
Originally Posted by Photo Engineer
the amount of chemistry needed to clear within some fixed
time; currently 4 minutes. Recall I use fixer one-shot.
Test are done with 5x7 sheets, with a water presoak. More of
a real world test at least for those who water stop. The ST-1
test will produce a silver sulfide stain if fixing is inadequate;
silver left in the emulsion. I believe a full wash is needed
do to residual fixer will carry some little silver.
BTW, films and papers vary in the amount of fixer and
time required. Dan