Forgot to prewash c41...problem?

shuttershane · Apr 3, 2012

Hey guys,

Yesterday I developed one roll of c41 film and forgot to pre-wash. Will this be a problem with my developer? It's only a few days old and I still should be able to run 4 or 5 more runs.

newcan1 · Apr 3, 2012

I never pre-wash. I preheat the dry tank in a water bath. I found that pre-washing could introduce color crossovers in the shadows. So I can't see how not prewashing would affect your developer.

markbarendt · Apr 3, 2012

Not a problem.

RPC · Apr 3, 2012

Opinions vary on this, some use a "prewet" or "prewarm" before the developer to facilitate uniform development and correct temperature. The term "prewash" is a bit of a misnomer, as at this stage it is not necessary to wash anything. Do whatever works for you.

Jeff Kubach · Apr 3, 2012

I wouldn't worry about it.

Jeff

darkroom_rookie · Apr 4, 2012

Since I don't have a processor and am developing 4x5 sheets in a Jobo 3010 rolled back and forth on a table, I was advised to do two pre-washes. 39 degrees C, each 40 seconds. It may help if you want to (have to?) replenish the c41 developer.

hrst · Apr 4, 2012

Quite the opposite, the prewash may cause problems in small tank reuse process. It depends on whether you can remove the prewash water from the film well enough. If you cannot, the developer might dilute too much after a few runs to cause some shifts. This is not a problem for one-shot processing, and it is not a problem for larger processors where the excess water is removed from the film with squeegees or air knives. And, it is not a problem if a possibility of comparably small density/contrast/color shifts does not matter you.

Photo Engineer · Apr 4, 2012

Prewash may lead to problems in mismatched curves (crossover) due to uneven temperature, and streaking due to uneven development. It is only going to reveal itself when you scan or print the negatives.

PE

shuttershane · Apr 5, 2012

I appreciate the replies. I did notice streaking on some rolls I did last week. It wasn't real bad but still noticeable.

Photo Engineer · May 11, 2012

Photo Engineer said:
Prewash may lead to problems in mismatched curves (crossover) due to uneven temperature, and streaking due to uneven development. It is only going to reveal itself when you scan or print the negatives.

PE

Someone pointed this out to me. I have been unclear here.

An improper prewet may lead to streaks and crossover, but a properly done prewet that evenly swells and tempers the film will not hurt, but rather it will help film. It leads to more even development and it reduces the chance of airbells (airbubbles or pinholes). However, it does dilute the developer more than a process done without a prewet.

PE

madgardener · May 13, 2012

PE; When you say a properly done prewet, how is that accomplished? What is the procedure? I'm assuming its more than just pouring 100 degree(f) water into the tank (paterson in my case), swishing it around a couple times and dumping it out?

hrst · May 13, 2012

The key here is to use two cycles of tempered water instead of just one, because a small volume of water is not enough to bring cool film and tank up to the specified temperature. After putting in the developer after 1-cycle prewash, it comes close, but might be out-of-tolerances. Using two cycles ensures it will be within tolerances.

Fill, dump, fill, dump. Measure the temperature of the water just before filling, especially on the second cycle.

Some people have preferred using one cycle at process temperature plus approx 1 degC. It is not very precise, though.

Photo Engineer · May 13, 2012

I think that the above post says it all.

PE

wogster · May 15, 2012

hrst said:
The key here is to use two cycles of tempered water instead of just one, because a small volume of water is not enough to bring cool film and tank up to the specified temperature. After putting in the developer after 1-cycle prewash, it comes close, but might be out-of-tolerances. Using two cycles ensures it will be within tolerances.

Fill, dump, fill, dump. Measure the temperature of the water just before filling, especially on the second cycle.

Some people have preferred using one cycle at process temperature plus approx 1 degC. It is not very precise, though.

I wonder if it would help, if the first cycle is a little cooler, say your room is 20C and you need 38C, make the first wet at say 30C this should bring it up to about 29C, make the second 40C, that should bring the film and tank up to about 38C, close enough that the developer can finish the job. This would make for less chance of reticulation, although I don't know it that's an issue with colour films.

hrst · May 16, 2012

There is no reticulation from pouring water at the process temperature directly, so you can just do it to get to the right temperature as closely as possible with minimum effort possible. Color films are almost impossible to reticulate.

Of course, if your film is at extremely low temperature for some reason, say, almost at freezing, you may want to add a third step. Then the first one could be of intermediate temperature.

Forgot to prewash c41...problem?

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