Warped Negatives!

luckycharms · Aug 18, 2008

Hello all. I stumbled across this forum looking for F76+ 1:19 info, and I am amazed at the wealth of analog info. I'm pretty much learning all of this on my own- I scored a Ricoh KR-5 Super II on eBay when I really just wanted the lens for my digital body, but I put a roll of black and white film in it and fell in love.

I hope this hasn't been discussed to death (though a search didn't turn up anything). I've more or less been able to figure things out using the magic of the internet and massivedevchart, but one thing continues to bother me: I hang my negatives using weighted clips and run a film squeegee over them a few times, and while the weighted clip on the bottom keeps them drying straight, they are developing a side-to-side warping, maybe 1/4" in total depth once they're dry. Picture a PVC pipe cut in half the long way and you have the rough idea, while it isn't that extreme. A friend seems to have suggested that the squeegeeing may be doing this, but I feel like letting them dry just a bit curved from top to bottom would prevent the warping. Any thoughts? I'd really like to keep squeegeeing rather than having to add something like Photo Flo to the mix. Your help is greatly appreciated.

Kevin Caulfield · Aug 18, 2008

Firstly, most including I, will caution against squeegeeing film. I now just run my fingers along the film, after using a similar product to Photoflo. One too many scratches will make you decide against the squeegee, and if you squeegee without using Photoflo, you will almost certainly get more scratching. Several films are prone to warping, sometimes lengthwise and sometimes side to side like yours. After you cut them into strips and sleeve them, if you leave a couple of telephone books (remember them?) on top, you should cure most of the warping.

srs5694 · Aug 18, 2008

I'll second Kevin's comments, especially in light of the original comment about "...run[ning] a film squeegee over them a few times..." -- I cringed a bit at the words "a few times." If you feel you must squeegee, do it once to minimize the risk of scratches. I squeegeed when I first started doing B&W processing because "official" sources all seem to recommend it; but I stopped a while back after getting some suspicious scratches and I haven't started again.

As to the film curl, unless it's bad enough that you can't get the film into an enlarger or film scanner, I wouldn't worry about it. If it's bad enough to cause problems, consider changing the brand of film you're using. They do curl differently. Generally speaking, the bigger names (Kodak, Ilford, and Fuji) produce film that curls less than the smaller manufacturers (Foma, Efke, etc.). Some people seem to have more problems than others, though. Whether that's because some are more bothered by an objectively similar amount of curl than others or because of objective differences because of batch-to-batch variability, different drying conditions, etc., I don't know. I've noticed that film I've had for a while (frozen bargain film stored in my freezer for a couple of years, say) tends to curl more than fresher film.

David William White · Aug 18, 2008

I've got some half-baked theories:

1) the faster film dries (more air movement), the more it curls,
2) the greater the temperature differential between chemistry/rinse and the air temperature, the more it curls,
3) the thicker the film base, the more it curls,
4) the narrower the film format, the more it curls.

Anything, anyone?

Ian Grant · Aug 18, 2008

So why are my films no different when dried here in Turkey, it's 38°C at the moment, compared to when I'm in the UK and its 16°C

It just depends on the film base used,pure & simple.

Ian

Ray Rogers · Aug 18, 2008

Maybe I missed something, but it has been my experience that 35mm flim does curl edgewise;
If it did not, the necessity for pressure during enlarging or conact printing would be much reduced.

It seems like the curl decreases after processing and storage in sleeves over time; some old negatives becoming quite flat.

Is it possible you are describing the normal expected curl?

Sheet film may be flat, but not my 35mm stuff....

Also, I do think curl can be manipulated by drying conditions; residual moisture level and stress during drying... depending upon the material.

Pete H · Aug 18, 2008

Ian Grant said:
So why are my films no different when dried here in Turkey, it's 38°C at the moment, compared to when I'm in the UK and its 16°C

It just depends on the film base used,pure & simple.

Ian

I beg to differ, Ian. When I moved to Oslo from the UK, I found much more curl in any given film. The relative humidity here is very low compared to the UK, and keeping drying temperature, film type, etc, the same, it is the only variable left. Films dry here in a couple of hours whereas I used to leave them 5-6 hours back in sunny Surrey.

The heavy book treatment seems to work fairly well, though.

cheers
Peter

dancqu · Aug 18, 2008

luckycharms said:
I hang my negatives using weighted clips and run a film squeegee
over them a few times, I'd really like to keep squeegeeing rather
than having to add something like Photo Flo to the mix.

I don't know how there could be a conflict twixt Photo Flo
AND squeegeeing. I used a sponge type for years and do not
recall any problem. I've now a small eight blade by Jobo that
works like a charm.

With water alone some difficulty is encountered. With the
film given a short soak in half strength Photo Flo and the
squeegee too, a single slow stroke does the job. Film
dries fast.

That Jobo by the way sells under other brand names.
I suspect there is a lot of knocking prior to trying
amoung those who rail against the use of a
Film squeegee. I wouldn't be without. Dan

Ian Grant · Aug 18, 2008

dancqu said:
I don't know how there could be a conflict twixt Photo Flo AND squeegeeing.

If you had a relatively soft emulsion then squeegeeing could easily cause a major problem, such as described.

Certainly if you put a squeegee anywhere near EFKE films you'd have problems.

Ian

Larry.Manuel · Aug 18, 2008

Try drying in higher humidity.

This is an APUG tip I found: wet the walls of a shower cabinet and hang the film to dry there, with door or curtain shut. I've found my films dry much flatter, with the prolonged drying time. This applies for 35mm and 120.

When drying more slowly, the Photo-Flo has a better chance to let the water run off, and I find no water spots. No squeegeeing for me.

Neal · Aug 18, 2008

Dear luckycharms,

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.

Welcome to the dark side,

Neal Wydra

removed account4 · Aug 18, 2008

luckycharms said:
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 ...

have fun + welcome to apug

john

George Collier · Aug 18, 2008

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?

panastasia · Aug 18, 2008

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.

srs5694 · Aug 18, 2008

Ray Rogers said:
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.

Simplicius · Aug 18, 2008

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.

Ray Rogers · Aug 18, 2008

The Inversion Bop

srs5694 said:
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.

Vaughn · Aug 18, 2008

srs5694 said:
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

luckycharms · Aug 18, 2008

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).

fschifano · Aug 18, 2008

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?

dancqu · Aug 19, 2008

Ian Grant said:
If you had a relatively soft emulsion then squeegeeing
could easily cause a major problem, such as described.
Certainly if you put a squeegee anywhere near EFKE
films you'd have problems. Ian

How about 1950s Adox? Or a few other films from
that era? I've ALWAYS squeegeed roll films. With
today's hardened emulsions there is even more
assurance that squeegeeing is safe. Buy the
eight blade; great design. Be sure to keep
it clean. Dan

Ian Grant · Aug 19, 2008

1950's German Adox was the same as 1970's EFKE ADOX, extremely soft.

Modern Adox is slightly better but use a squeegee with it and you'll damage it.

Ian

Ray Rogers · Aug 19, 2008

The smallest of life's simple pleasures

dancqu said:
How about 1950s Adox? Or a few other films from
that era? I've ALWAYS squeegeed roll films. With
today's hardened emulsions there is even more
assurance that squeegeeing is safe. Buy the
eight blade; great design. Be sure to keep
it clean. Dan

To be fair, I do not think it is the squegee, sponge or cloth that is the real problem...

A lot of film has been so treated without problems.

I think the trouble is with dust, grit or other solid particle(s)
getting lodged between the soft film (no matter how hard it is!) and
the person doing the drying.

Yes you can do it with out scratching the film,
but I/we/many prefer just letting the liquid flow off naturally...
I have seen dust (even grains of sand) get stuck in those squeegee blades...
a lot depends on how you store them when they are not in use.

Squeegeeing (prints at least) is actually sort of fun and
strangely rewarding for someone who is thrilled by the smallest of life's simple pleasures!

JBrunner · Aug 19, 2008

Use photoflo. Don't squeegee. After the negs are dry, curt and sleeve them and put them under a book.

Ask yourself why you need to squeegee film, what is the benefit, really? If you use a wetting agent there is no compelling reason to run anything physically against and possibly abrasive to a wet and therefore fragile emulsion. Sqeegeeing is an outdated carryover from the really olden days.

srs5694 · Aug 19, 2008

JBrunner said:
Ask yourself why you need to squeegee film, what is the benefit, really? If you use a wetting agent there is no compelling reason to run anything physically against and possibly abrasive to a wet and therefore fragile emulsion. Sqeegeeing is an outdated carryover from the really olden days.

When I first started (not that long ago -- 2005 or thereabouts), I couldn't get film to dry without drying marks unless I squeegeed, so there was a real benefit. Now I no longer have that problem, I believe because I've cut the amount of concentrated Photo Flo I use from the recommended dilution to twice as dilute (half the concentrate in a liter of water). Peoples' experiences on this point seem to vary an awful lot, so it's hard to give a single procedure that works for everybody -- variables like the water supply, brand of wetting agent, and perhaps even environmental factors seem to greatly affect results.

Warped Negatives!

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