Question on Flattening 120 Film After Drying

[GregY]

Yes, I suppose… but with these quantities of films and the delay, there’s no other way.

It sounds as though you're running a commercial operation?
I had films processed by Atelier Publimod last time i was in Paris. The work was quick and resulting negatives were flat. If you're running a commercial lab, you must have colleagues in the business. Surely you'd get better info than asking on an internet forum?

 

[pentaxuser]

The temperature is set to 44 °C, and the films remain there for approximately 30 minutes.

My film dries in about 20-30 mins in room temperature which is no more than 20C Your temp and time seems very high to me I base this statement on one experience in a college darkroom with a heated dryer where a fílm had begun to curl after about 15 minutes

pentaxuser

 

[Kino]

You might have to experiment with what the optimal humidity is for "dried" film. Just drying wet film with totally dry air is a sure-fire means of having emulsion curl strongly.

Properly "dry" film is not 100% dry; you have to have some humidity for the emulsion to relax and come to equilibrium with the tension of the base.

On a motion picture processing machine we ran, the film was put through 3 linear dry boxes at a rate of anywhere from 70 to 110 feet per minute with a wet to dry time of 2 to 4 minutes. The air temp was high BUT the air was not bone-dry; it had about 20 to 40% humidity, depending on the film stock being processed and the speed of the processor.

You might experiment with filtered, humidity controlled air with a slightly extended dry time for flatter negatives.

You can also have a secondary dry box AFTER your scanning process, if the film is too humid to sleeve and ship.

 

[djdister]

Yes, I suppose… but with these quantities of films and the delay, there’s no other way.

It's hard to imagine a scenario where 120 film processing would be in such a rush...

 

[MattKing]

It's hard to imagine a scenario where 120 film processing would be in such a rush...

I can certainly remember such a time - in the days when 120 was king in the commercial photography world.
But I expect that the real issue for a commercial lab is that they need the dryers to empty so they can run the next batch of film for customers.