I'm finding that my rolls 120 Delta 400 (new) are drying with what I would consider excessive curvature towards the emulsion side of the film. The curve is an arc which makes the film look like a quarter of a cylinder sliced lengthwise. I normally would expect a little bit of curvature due to shrinkage of the gelatin, but what I'm seeing is excessive and this is making printing a bit difficult.

I am suspicious of either my process or the low humidity here in Colorado. My processing uses a Jobo CPE-2: (1) water presoak for 1 minute, (2) develop, (3) 4 15-second water stop baths, (4) fix for 3-1/2 minutes, (5) water bath for 1 minute, (6) hypo-clear for 1 minute, (7) water bath for 1 minute, (8) bubbling cold water rinse for 10-minutes, (9) hang to dry with weighed clips and give a good soaking spritz with distilled water in place of an anti-spotting wetting agent soak.

Anyone have insight as to what is going on and a remedy?

-- Steve Wahl (stevenbwahl@earthlink.net), March 27, 2002

Answers

Steve,

I think this is just a characteristic of the film base. the curl is far greater than TMY TMax 400 on a 4 mill Estar base. this is one of the reasons why I most likely will not use this excellent film more. I cut the negatives in threes, jacket them, and set a plate on them overnight. it helps, though TMax films are virtually planar out of the tank which aides scanning.

-- daniel taylor (lightsmythe@agalis.net), March 27, 2002.

I find Delta 32000 in 120 does a similar thing. I don't worry about it, once it has been stored flat for a while it becomes a non-problem.

-- Robin Smith (smith_robin@hotmail.com), March 27, 2002.

Curling depends on the thickness and hardening of the emulsion. Thick emulsions with less hardened gelatine (e.g. APX 400) curl very strong. Films like Tmax 100 are the opposite extreme. The thickness of the film base and the coating of the "blank" side my also play a role. In gerneral, it's not a quality criterion, unless you want to make prints with a glassless neg holder immediately after processing.

-- Georg Kern (georg.kern@uibk.ac.at), March 27, 2002.

I don't experience this problem with Delta 400. My final wash is a bath in some bottled water (I think it's de-ionised.. but don't tell Ed!) with Ilford Wetting agent, hang them with a weighted clip (35mm one at that so it only grabs the middle section) on the bottom and let dry.

-- Nigel Smith (nlandgl@unite.com.au), March 27, 2002.

Curling towards the emulsion is pretty typical for LOW hunidity and rapid drying that it causes. What worked for me was to get a metal cabinet and place a pan of water on the bottom. Then dry the film at least 12 hours with cabinet door closed. This raises humidity a lot and does away with curling. Best, Howard

-- Howard Posner (hposner1@swarthmore.edu), April 01, 2002.