How long does the final wash need to be when developing film?
Asked 7/8/2019
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When developing film, how long does the final wash really need to be to remove fixer adequately? Some sources suggest about 10 minutes, which seems long. Is there a practical minimum, and does it depend on using a running-water wash versus an inversion-and-refill method such as Ilford’s?
Originally by Photography Stack Exchange contributor. Source · Licensed CC BY-SA 4.0
Photography Stack Exchange contributor
7y ago
2 Answers
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The purpose of the final wash is to get all of the chemistry (really, the fix) out of the film (or paper). If you don't do this then your film will be damaged by the chemistry over time. It's hard to tell how much chemistry is still in the film, and washing is a very easy process to do, so people tend to be very conservative.
Ilford did some research on this a while ago, actually measuring what was left in the film, and discovered that washing by changing the water in the tank & inverting a bunch of times was very effective. They have some instructions (for their chemistry!) here (PDF link).
What I do is an exaggerated version of the Ilford thing: I do 20, 50 & 100 inversions changing water between each set & then leave the film to stand in another change of water for 10 minutes, finally using yet another change with photo-flo in it. This is excessive and I feel bad about using a lot of water, but I really want to know my film won't get eaten by the fixer, and I've seen too many old prints which have been. And of course you can do other stuff in the final 10 minutes (like rinse & dry all the graduates, put the chemistry away &c &c).
Originally by user82065. Source · Licensed CC BY-SA 4.0
user82065
7y ago
0
Generated from our catalog & community — verify before relying on it.
The final wash is there to remove residual fixer; if too much remains, the film can deteriorate over time. So the “minimum” depends on your goal:
- For a visible image right away: essentially no wash is needed, but the film will not be archival.
- For long-term stability: wash thoroughly enough to remove as much fixer as practical.
A full 10-minute running-water wash is a conservative standard, not always a strict requirement. Community answers point to the Ilford-style inversion-and-refill wash as an effective alternative: drain and refill the tank, then do multiple rounds of inversions with fresh water between rounds. This can remove fixer efficiently without a long continuous wash.
In short, 10 minutes is not necessarily the true minimum, but some adequate wash is important if you want negatives to last. If you want an efficient method, use the manufacturer’s recommended wash sequence for your film/fixer system, especially inversion-and-refill methods designed to reduce wash time while still achieving archival results.
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