Why is my film curling so?

[brianentz]

When I process my tri-x, t-maxx, etc... My film sure curls lengthwise a lot. What might I correct?

 

[Rick A]

Sheesh, another my film is too curly thread. Keep it on the hanger and weight the end, dry for 24 hours. Hang it in the shower after you steam it(the shower, not the film) for a few minutes, close the door and let it stay muggy in the room while drying. Press the cut film between the pages of a heavy tome.

 

[Mainecoonmaniac]

One thing might help is drying your film with a weight on the bottom. Some film like the older type of Foma will stay curly no matter what.

 

[DarkroomExperimente]

when you say "curls lengthwise" do you mean it curls around the long axis of the film? In other words, opposite edges of the film end up curling towards each other. Some of my homemade developers do that to my film and hanging with a weight does nothing to help.

 

[baachitraka]

I just ordered Fomapan 100 and 400(bulk roll).

After reading the threads with similar topics, let me wonder why does curling pose a problem.

Normally, I hang it with Paterson clips after development and cut into strips of five exposures and store in those sleeves.

 

[brianentz]

I mean the edges, not the ends, curl toward each other. Of course I hang them with a weighted clip, so curling in the other direction isn't a problem.

 

[brianentz]

Someone suggested letting it stay in a humid environment while drying. Does drying it too fast cause it to curl (edges toward each other)?

 

[tkamiya]

I have this problem. Allowing it to dry slowly seems to help a little but still pretty curly. The only thing I can do is just let it dry, put it in negative sleeves and let it sit for few months... They will eventually flatten out. Some film tends to curl more than others. Besides it being annoying, it really does no harm in enlargers.

Placing it under weighted glass for few days did absolutely nothing.

 

[Rick A]

The malady the OP is obviously refering to is called "cupping". The cause is the emulsion layer being a different substance than the base of the film, when dried it shrinks more than the base material. I have a feeling that some with this excessive problem have probably left the film in liquid for longer than necessary, causing more expansion initially, resulting in excessive shrinkage upon drying. I shoot Chinese film that most complain that it cups and curls, but have personally experienced minimal signs of it, Foma does exhibit some tendency, Ilford, Fuji, and Kodak almost none in my experience.

 

[DarkroomExperimente]

the only thing I've noticed is different developers do it...my Quercetin developers put a lot of curl/cupping into the film, the others don't

some of my film spends 3 or more hours in liquid without any curling issues

 

[Thomas Bertilsson]

The malady the OP is obviously refering to is called "cupping". The cause is the emulsion layer being a different substance than the base of the film, when dried it shrinks more than the base material. I have a feeling that some with this excessive problem have probably left the film in liquid for longer than necessary, causing more expansion initially, resulting in excessive shrinkage upon drying. I shoot Chinese film that most complain that it cups and curls, but have personally experienced minimal signs of it, Foma does exhibit some tendency, Ilford, Fuji, and Kodak almost none in my experience.

Your geographical location makes a huge difference, because it's humidity related. I live in Minnesota, which has some of the biggest differences in humidity in the world, comparing summer to winter. Bone dry like the desert in the winter, and often 90% or more in the summer.

In the summer my negatives dry flat, and in the winter they don't.

 

[Neal]

Dear brianentz,

Just ignore it. The film will flatten nicely over time. If it really bothers you, follow the advice from Rick A. It will help.

Neal Wydra

 

[oldfaithful58]

Your geographical location makes a huge difference, because it's humidity related. I live in Minnesota, which has some of the biggest differences in humidity in the world, comparing summer to winter. Bone dry like the desert in the winter, and often 90% or more in the summer.

In the summer my negatives dry flat, and in the winter they don't.

Thomas is correct and that is what I experience in Finland. The relative humidity of the air in the room when drying the film needs to be as near as possible to 50%. In winter in Finland, the dry air brought into the house and warmed up to 20c has a relative humidity of 20 to 25%. The film curls like hell.

Flattening the sleeved film under a pile of books after it is TOTALLY dry can improve it a lot. Beware that the film can get damaged if still slightly damp, because the pressure "embosses" the texture of the sleeve into the emulsion.

Dave

 

[Thomas Bertilsson]

The relative humidity of the air in the room when drying the film needs to be as near as possible to 50%. In winter in Finland, the dry air brought into the house and warmed up to 20c has a relative humidity of 20 to 25%. The film curls like hell.

For me, 'curling like hell' means a roll of 35mm Tri-X cups around the entire length of the film a good 120-150 degrees, almost half a circle. Not as extreme as the attached picture, but really close.

In storage it takes my negatives about a month to flatten to the point that I can put them in a scanner and scan them. The enlarger is obviously better since the neg carrier flattens them nicely, but sometimes they can be tough to align without somehow damaging them.

 

[DesertNate]

If your humidity is really low, your negatives will dry very quickly. This can lead to cupping. If you're talking about curling (spiral form curls), then you're failing to dry the film with a weight to straighten it.