Larry, Moe & Curly: The Secret to Flat Negatives

By Johnny Martyr

I'm positive about the negative, but a little negative about the positive. - Curly Howard

If you process your own film and don’t live in the tropics, you’ve probably run into an annoying problem that I see discussed in forums ad nauseam – curly and cupped film negatives.

Let me set the scene: you’ve just taken some great photos, you’ve processed the film successfully and when you hold the still wet images up to the light for the first time, they look amazing. You can’t wait to scan and share them. So you leave the negatives to hang and dry for a few hours before cutting and sleeving. But when you return, you notice that your film is curling and cupping. If you place these negatives in a carrier for scanning, not only will they fail to fit into the carrier properly, you’ll get Newton Rings or out of focus corners depending on your scanning method.

Don’t be a knucklehead!

Let’s start with understanding the problem.

WHY DOES FILM CURL?

Roll film is made up, essentially, of two parts; a base (the material that holds the image) and an emulsion (the material that makes up the image). The base and emulsion are opposite sides of the film and like most substances, because they are comprised of different materials, dry at different rates. Imagine washing a load of mixed laundry. If you open the dryer early, you may find that your t-shirts are dry but your socks and jeans are not. Just as shirts and jeans are made of different materials and dry at different rates, so does the base and the emulsion of your film.

Unlike your laundry though, the base and emulsion of film are stuck together. So when one dries before the other one, the drier side shrinks and constricts against the wetter side which is more mailable. If left to their own devices for long enough, both sides of the film will eventually dry and the film will flatten out naturally on its own.

But this could take some time and you want to scan your film and get photos up on IG yesterday!

So look, there are two ways to address any problem – 1-prevent it from happening or 2-fix the problem after it occurs. Depending on various things, you may choose either method. Neither is bad for your film.

PREVENT THE CURL

Probably more than any other form of artist out there, photographers love to blame their tools for their own lack of knowledge or skill.

To avoid curly negatives, some people will tell you to switch brands of film or to use heavier drying clips.

In one discussion I saw a commenter tell the original poster, who was using Kodak film, to switch to Ilford because it dries flat. And in another discussion, the original poster was using Ilford so someone else recommended switching to Kodak.

I once saw someone recommend heavier clips, to which the OP replied that they do use heavy clips. Comically, though I’m not sure if it was intended to be, the commenter said they needed to be heavier then!

Do some makes and types of film dry flatter than others? Sure. Is using those cool, stainless steel drying clips more satisfying than using binder clips? Of course.

But let me let you in on a little secret. There are no bad films and there are no bad film drying clips. There are only consumers who don’t fully understand what they are doing with these fine products.

Different manufacturers use different materials when making different types of film. Yes. But one particular brand is no curlier than another anymore than one brand of lens is inherently better than another brand. There are reasons for different behavior of products. And these are as much environmental as they are based on the product. So there’s at least two parts to the equation; materials and environment.

I live in Maryland, it’s fairly humid here but the climate is also pretty volatile because we’re close to the Atlantic, and we have all four seasons. The weather can be ever-changing here. During some months of the year, I can literally process the exact same brands/types of film in the morning as in the evening, with the exact same processing method, and the morning rolls will be flat but the evening rolls will be so curly that they look more like weird soda straws than film negatives.

Is this anything at all like your experience in a different state or country? Just like I noted in my argument for the use of squeegees, we have to stop propagating mythology based on personal experiences alone.

So what is the common denominator across all our curling issues with various makes of film in different regions?

Humidity. Not only does warm/hot humid air combat static and dusty negatives, humidity helps even out the drying times of the emulsion and base sides of the film.

Notice that, regardless of the brand film you shoot, when you get negatives back from a lab, the film is always flat. This is because labs use drying cabinets of various types before they sleeve film.

A drying cabinet not only heats film at a safe temperature but it is also humid inside them. At home, many photographers will hang their film on the shower curtain rail of their bathroom after running a hot shower to steam up the room. Same principle.

As I noted there are two ways to handle any problem – to prevent the problem and to fix the problem after it’s occurred. So what can we do after the problem has occurred?

REVERSE THE CURL

Unlike other types of problems, your film will eventually dry flat on its own volition. So there is no real harm (that I’ve encountered) in allowing your film to dry curly and then flatten it before scanning. This may seem like you’re not really resolving the problem and just putting a Band-Aide on it. And you are welcome to view it that way and prevent the curl with my previous recommendation. But for my particular workflow, I am content simply reversing the curl.

So here’s what I do.

Here are ten rolls of cut and sleeved TMAX 100 and Tri-X 400 that I processed and left hanging to dry overnight. The film was flat and wet when I hung it and the next morning it was cupped and dry to the touch. Outside the temperature was 40°F with 40% humidity and in the particular room where I dry my film, I believe it was about 65°F with 50% humidity.

In order to be completely scientific about this, I would need to monitor and measure the amount of curl, temperature and humidity throughout the drying time but I’m just a photographer trying to get his work done and to explain to you what I’m doing when I have a few minutes so I hope you’ll excuse my practical approach!

And in case you were wondering, I typically leave my film hanging to dry either overnight or for 2 to 3 hours. It totally just depends on how much and how fast I can and need to work. When I’m really busy, I have 20 rolls hanging to dry with about an hour between each batch of 10 and then I remove the first 10 and hang another 10 within an hour or two sometimes while the negatives are still slightly damp and difficult to sleeve.

It’s slightly off topic but also don’t forget that it is manufacturer recommended to process soon after shooting. So don’t throw your exposed film in a refrigerator and get to it when you get to it. For best results and return on your investment of time and money, process within a few days of shooting!

Anyway, so I took all ten negative sleeves and rolled them against the curl like I was rolling up a newspaper or magazine that my work was featured in. Then I stuck them in the handle of my Mac Pro and left them there for an hour.

How long the film needs to rest in the reversed roll depends on how bad the curl is and how quickly it can continue to dry based on whatever environmental and product factors.

The results will not be perfectly flat negatives initially. They will now be all wavy. But for flatbed scanning, the carrier holds the film flat enough for me to do my scanning and the negatives will only get flatter as I work through the scans. You can also just hold them in the reverse roll longer if necessary.

Many people will stack heavy coffee table books atop their film but I find this takes much longer.

The details of your workflow will of course vary depending on your digitizing method so I will leave it up to you to incorporate my recommendations into your particular situation.

Which leads me to my next point, which is also somewhat off topic if you don’t mind. Photographers who digitize their film with a digital camera are always trying to sell me on their method and to ditch my flatbed, citing numerous points of data of which I’ve been aware for the last twenty years. But when you have a workflow that is effective for your goals, swapping a big element like that requires retooling everything around it. Hell, even the Print File negative sleeves that I buy were chosen based on my scanning method. So we can have arguments all day about the “best” digitizing method, but while these folks are debating, I’m getting work done.

Larry and Moe

Okay, so we took care of Curly but what about Larry and Moe?

They can get their own blog!

We can all look like stooges sometimes when tackling issues with home film development, so just remember the wise words of Curly Howard: