Foggy Film

Once you start developing your own black and white film, people tend to give you the old film they have. This is both great and not so great, though always nice of them to think of the film photographer in their life! Accept the gift and give it a try, you never know what you’ll get, and if the film is unusable in camera, there are other creative things you could do with it.

One of the issues with old film and paper is age fog. Age fog appears as an even density increase over the whole piece of film. You can see it after it has been developed in the rebate areas as a grey tone that isn’t there in a fresh film. The density can range from slight to so much that the image is hard to distinguish. Film with extreme age fog is usually less able to produce image density, and the film won’t be usable. There are many factors that affect film and cause age fog. The biggest one is storage. If the film has been stored in a warm environment, it can become fogged over time. This is true of film that hasn’t passed its expiry date too. If you leave a roll in your hot car all summer, there’s a good chance it will have some fog. Store your film in a cool or cold place like the fridge or freezer, and it will still be good in 10 years when you find it behind a long forgotten bottle of plum sauce or frozen loaf of bread. To make things confusing, certain developers may cause some additional base fog (non image silver in the film – the film base can also contribute density), as can developing techniques, temperature, exhaustion of the developer, and other variables. Here I will look at age fog specifically and one method of reducing it during processing.

Beau has started carrying Flic Film’s Fog Off. This is a chemical added to developer to help reduce the extra base fog in old film and paper stock. It is a 1% solution of Benzotriazole, which acts as a restrainer during development. (It is a chemical that could cause skin irritation and serious eye irritation, though this is a low concentration. All chemicals used while developing film can be an irritant or have the potential to cause health issues, so use good chemical handling practices while doing any processing.) There are general instructions on the bottle for using Fog Off, but you will have to test and keep good notes to find what works best for your film/developer combination. Different developers will help reduce fog, or not add chemical fog, so it’s worth it to try different developers as well, especially if you have a lot of the same film.

Test #1
The first test I did was with long expired TMAX 100 sheet film. The expiry date was January 1995! I exposed it one stop over to account for the possible lower sensitivity of such expired film, though I did develop it as normal. The first sheet was developed with no Fog Off added to get an idea how fogged it was and have it to compare to. As an experiment, it failed because it turns out this film had no visible age fog! Nothing to correct. To try and get something out of the effort, I developed the rest of the sheets in various developers to see what the differences would be. This will be the next blog post so watch for it!

Test #2
Marley was given some expired Ilford HP5 so I thought I’d try the Fog Off on that. These are very informal tests. I didn’t shoot a whole roll of the same image, though I did shoot all images in the same location and tried to keep the light the same. The film is over exposed by about a 1/2 stop. I measured and processed consistently so it should give a good idea what effect the Fog Off has in this situation.

Film: Ilford HP5 35mm – expired in 1998 – storage situation unknown
Developer: Ilford Ilfosol 3 – 1+9 – 20C
Stop, fix, and rinse as normal

All scans done on the Epson V800 Photo flatbed scanner.

#1 – Developed 6.5 minutes with no Fog Off
#2 – Developed 6.5 minutes with 5ml Fog Off added to developer
#3 – Developed 6.5 minutes with 10ml Fog Off added to developer
#4 – Developed 9 minutes with 5ml Fog Off added to developer

#1 – Developed 6.5 minutes with no Fog Off
#2 – Developed 6.5 minutes with 5ml Fog Off added to developer
#3 – Developed 6.5 minutes with 10ml Fog Off added to developer
#4 – Developed 9 minutes with 5ml Fog Off added to developer

I found that the film isn’t too badly age fogged and could probably be used as is, especially if you are scanning it since it’s easy to adjust for the extra density. Adding 5ml to 300ml of developer required to cover the roll of 35mm in the Paterson tank appears to reduce the age fog. There is still a bit of density there but it’s much less than before. Adding 10ml of Fog Off reduced the base fog even more but did make the shadow detail thin in comparison to the others. I thought I’d try adding some time to the development and using 5ml of Fog Off to see if I could create a bit more density in the image, but it also increased density in the base fog so maybe not the way to go.

I also did a detailed scan to look at the grain and shadow detail, and found some interesting results. In the first row with no Fog Off, the grain looks as expected for HP5, a bit grainy with normal shadow detail. The addition of 5ml of Fog Off seems to have lessened the fog nicely and the grain seems similar. The third strip with 10ml Fog Off added shows reticulation in the film. The time and temperature was the same as the previous strips. I repeated this experiment to check this result – see the results below. The fourth strip with less Fog Off and added time resulted in coarser grain and more density in highlights, as expected with the additional development.

1st strip
Normal development with no Fog Off

2nd strip
Normal development with 5ml Fog Off

3rd strip
Normal development with 10ml Fog Off
Note the reticulation

4th strip
Added development with 5ml Fog Off

Reticulated film
3rd strip from first test with 10ml Fog Off added. Click to enlarge.

Re-test using the same film stock, developer and Fog Off combination to see if it would reticulate again – it didn’t.

Reticulation in film is generally caused by extreme changes in temperature while processing. It is the gelatin layer and the silver grains suspended in it contracting and expanding with the temperature changes and forming the pattern you can see in the first test. It’s often not somthing you want, but you can purposely put the film through extreme temperature changes for artistic effect. Modern emulsions are less prone to reticulation so you will have to work at it.

Test #3
To really test the Fog Off, I found two rolls of Ilford HP4 that expired in February 1974. I wasn’t sure where to start with this so I decided to bracket the frames at 2 stops over and 3 stops over. As I mentioned, this is a very informal test and I didn’t shoot these images of the same subject or on the same day so there is some variation in the image density. Not ideal but it’s what I had to work with.

Film: Ilford HP5 120 – expired in 1974 – storage situation unknown
Developer: FlicFlm BW&G  – 20C
Stop, fix, and rinse as normal

All scans done on the Epson V800 Photo flatbed scanner.

Ilford HP4 film developed in FlicFilm Black White & Green. The strip n the left has 10ml Fog Off added to the developer, the strip on the right has no Fog Off added.

Positive of the negatives. Slight adjustments were made to the whole of the file to make the image more neutral and adjust the contrast.

Both films were developed for the same time in FlicFilm’s Black White & Green developer. The strip on the right is with no Fog Off added, the strip on the left has 10ml Fog Off added to the developer. They were shot at different times so the exposures are not exactly the same, which doesn’t make for the most precise test. Although the scenes were metered, the added density in the image area is possibly due to exposure differences since the day with the van was fairly bright, and the day with the building was gloomy and wet. Look at the space between the frames to judge the effect of the Fog Off. This density shows the amount of base fog and whether there was any improvement. In this case, the Fog Off really didn’t change the amount of age fog. Looking at the negatives, the base visually looks slightly less dense, but the eyedropper tool in Photoshop measures them to be about the same. Interestingly, when the file was inverted to a positive, it appears there is more fog in the strip on the right. I need to examine the files more carefully to try and understand this result.

I have found that when film is very expired, the Fog Off isn’t as effective. Further testing is needed to find out if adding more Fog Off to the developer will have an effect. I will have to go searching for more film that has expired in the 70s!

Some interesting results for sure! The Fog Off does help but should be used only as needed to avoid losing details in the shadows. Do some clip tests (cut off a short piece from the beginning of the roll and develop however you’d like to do the test before developing the rest of the film) to find out if the technique you want to try will work. Develop the first one normally to find out how much fog there is, then develop another adding the amount of Fog Off you think will work. This allows you to make some adjustments before committing to the whole roll. It is worth trying other developers as well since different formulations will produce more or less base fog.

You can also use Fog Off in paper developer to reduce age fog. There is a lot of expired paper in old darkrooms and it is worth it to try and make use of it. A certain amount of base fog in paper can give the image a softer look that is quite lovely, but this isn’t always what you might want. Testing Fog Off with paper will have to wait for another day and another post. In the meantime, if you have expired paper and want to know what to do with it, look at this post to get some ideas. https://www.beauphoto.com/what-to-do-with-an-old-box-of-photo-paper/

Another perspective is to look at the age fog as an addition to the image. When the negative is evenly fogged and not so dense that you can’t see the image through it, they can still be good for scanning. I have had nice results with scanned negatives that were fogged, and also negatives that were very thin. If you are printing in the darkroom, you may have more of a challenge. Don’t be afraid of fog if you are scanning the film, you might find some nice detail and grain, and it’s fun to use film that is so expired! Just know that when using expired film, there are no guarantees.

There are many variations of the development process for age fogged film, and a lot of advice on the internet. Do lots of testing and take good notes to find what works for you. If you find something that worked well, share your findings in the comments and let everyone know.

This is from a very expired roll of Ilford Pan F I found in a camera. When using expired 120 film there is often an issue with the ink from the backing paper imprinting on the film, leaving a pattern in the image. The ink is not necessarily archival and will off gas, leaving fogged spots on the film. These are not particularly usable, unless you like the look.