Not to worry. A curve in the direction of the emulsion is quite common. It will flatten in your negative carrier for printing/scanning and will flatten further over time in storage.
I'd really like to keep squeegeeing rather than having to add something like Photo Flo to the mix.
it only takes a drop of photoflo ( i am finally finishing a bottle i bought in 82' )
in your developing tank. just wash, fotoflo and hang your film.
if it curls a little bit, don't worry about it, just put it in your print file/sleeve
and put something ontop of it. the film will be flat when you
put it in the enlarger.
squeegees are good for drying prints, but i wouldn't bother to use them
for film ...
Squeegees work great until the day there is a small piece of dirt in the last rinse. I (like many) do the last rinse in distilled, with PFlo, and wipe GENTLY with a cotton material (called Webril Pad, a graphic arts thing, comes on a roll and won't scratch) that has been soaked in the rinse water and wrung out as well as I can. If I didn't have them, I would use a pad fashioned from cotton balls. After soaking, I roll the stainless nikor tank over it on a clean piece of plexiglass, like an old fashioned washing machine roller.
My experience with curl is that it varies at least from film to film (if not from humidity level to humidity level. I think it has something to do with differences in tension on either side of the film, created by the drying of the emulsion on one side, drawing in the edges as it contracts. Like when you drymount a print, the board usually curls toward the print side (contraction again). The phone book trick works for me, in most cases, although some films are quite militant about their curl. May have to do with emulsion thickness?
I've been using the same piece of Kodak photo chamois/shammy for years for removing water drops from roll film - sucks in every drop completely - and never used Photo-flo. Never had a dust problem or scratch with this method.
Drying film too fast will cause more curl.
__________________ "Pictures are not incidental frills to a text; they are essences of our distinctive way of knowing." S. J. Gould
Maybe I missed something, but it has been my experience that 35mm flim does curl edgewise;
I distinctly recall a post from PE in which he said that film can curl in either direction depending on how it was cut from the master roll. Apparently the initial curl in the master roll is an important determinant on this.
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In my limited experience all 35mm films have some kind of deformation after drying, some worse than others. I use a wetting agent and never squeegee and I hang all film to dry in a Store cupboard with two wooden clothes pegs at the bottom to keep them straight. With this technique I find the "market leaders" seem to only slightly curl across their width but hang and dry straight (I thought the curl was perfectly normal... until now). Fomapan seems to sometimes twist along the long length for some reason and dries "flatter" across the short width, in my experience, I usually add an extra clothes peg to the bottom to keep this twist out. I have had no problem with either in my enlarger and getting them flat. I would have assumed all film holders in enlargers are designed to keep the negative flat.
I distinctly recall a post from PE in which he said that film can curl in either direction depending on how it was cut from the master roll. Apparently the initial curl in the master roll is an important determinant on this.
I did not see PEs post, but yes, certainly orientation is of importance...
as is possibly the location (initial end or later, less tightly curved areas)
and the duration of storage.
However,
I have never seen a 35mm film that curled upwards* when the emulsion was face down.
From a design perspective, I wouldn't want to either.
(Well, actually wet 35mm film does "The Inversion Bop" when it dries. Slowly, it curves sharply, horozontally, shortways across the legnth, towards the base, but then losses that curl when drying nears completion... the only curl that remains being that towards the emulsion side)
But we were talking about final edge to edge curl in 35mm film and this wet curl is something different.
As an OT aside,
Recently I have been having trouble with poorly produced toilet paper not tearing the way I want it to when I ... uh, yeah,
OK.
Last edited by Ray Rogers; 08-18-2008 at 01:09 PM.
Reason: Flushed
I distinctly recall a post from PE in which he said that film can curl in either direction depending on how it was cut from the master roll. Apparently the initial curl in the master roll is an important determinant on this.
It is interesting to hear this. It has been my thought that the curl had nothing to do with the base material (or which way it is cut), but instead with the gelatin of the elmulsion layer. The gelatin swells when wet, shinks when dried -- and this change of shape pulls at the film base, causing the film to curl. The drier the gelatin, the greater the curl (thus more curl using heat or being in Oslo).
This is certainly the case in the production of carbon tissue -- a thick layer of pigmented gelatin on a paper or paper-like substrate. The stuff will always curl towards the gelatin side, just like film will always curl towards its emulsion side.
Gelatin wants to absorb some water from the air, so an equilibrium is probably reached over time and the film "relaxes" back to flatness. Fiber based paper does this also. One can press the prints flat to hurry the process, but if just left a box, the prints will eventually lay perfectly flat.
There is some "memory" at work, but I do not know if this is due to the gelatin or the base (or both) -- leave a roll of developed film rolled up and it is problem to get flat again.
Vaughn
__________________
At least with LF landscape, a bad day of photography can be a good day of exercise.
Wow, thank you all for your responses. I feel much better now knowing that the curl isn't something only I'm dealing with. I currently have four rolls or so worth of sleeved film sitting under a sizable book, and it's already helping to flatten them out. The chamois sounds like an interesting option, and I will look into it to decrease my odd of scratching my negatives, though I must say the convenience of the squeegee is something I will miss (if I do in fact give it up).
Look, you got a lot of advice here. Anything involving wiping wet film with a squeegee, chamois, sponge, etc. is lunacy. Use a wetting agent in your final rinse after the wash. Use only enough to prevent the water from beading up and NO MORE. Dunk the film in, and hang it to dry. There will be no chance of scratching the film or leaving anything behind that might stick to the emulsion. Yes it might take a little longer to dry, but the film will dry with less chance of cupping. Yes, it will drip on the floor. Use a sponge to clean that up. Are you in that much of a hurry?
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