Testing Black and White Film

Pick a day when there are no clouds and no wind. Find a scene that is in partial sun, and partial shade. Find a person who can serve as a model, or find a way to shoot your camera remotely, with either a timer or long cable release - and be your own model. The test image should contain recognizable tones, and a human face is best for that - because our brain specializes in reading faces.

Assemble a collection of well-known articles of differing textures and colors. Be sure to get something dark and something light. Place them in the shade and in the sun. Put a standard grey card in the scene, in direct sun. Make sure that the card is at an angle, with no shiny reflections. We want it to represent neutral grey. Place some glass, some wood, some cloth in the scene. Let the scene be close to home, so that you can return to compare the print and subject later on if you want.

Set up everything in advance. We want to take all the photos in a quick succession, so that the light is exactly the same for each photo. Practice if you like, but when it comes time to take all the photos, do them quickly. If you want to test indoors, you can do that if you must, but it's best to test a natural scene, and come up with a film speed/developer time which looks most like natural light. To repeat: we want the result which feels most like light.

Choose one lens and stick with it for all the exposures. It should be the lens you use most often. If it's a fairly modern lens, the actual shutter speeds will probably be very accurate. Even if it's an old lens, if the shutter is in fair condition, it will probably be pretty accurate. According to my Calumet Electronic Shutter Tester, this is most often the case. If you like, test your shutter - or have someone test it for you - and find out for yourself. But choose one shutter speed, and stick with it for all the exposures. Pick a common speed, like 1/60. Don't use 12 and 3/4 seconds, unless that's your usual shutter speed.

Get some pieces of plain white paper and a wide marking pen, and make a set of 3 labels. For example, let's say we are going to test TMax 400 film, which is also called TMY. Make a label that says "TMY 400". Another will say "TMY 800". Make another that says "TMY 200". Make sure that the lettering is large, so you can read them when you make prints.

Set your light meter to the speed recommended by the manufacturer. In this case, it's 400. You can use an incident light meter, or you can use a spot meter, and take a reading from the standard grey card. Let's say we get an exposure of 1/200 second at f/22. Place a label that reads "TMY 400" in the scene, in a prominent location. Expose 3 identical sheets.

Now stop-down the lens by 1 stop, to f/32, and replace the label with the one which says "TMY 800". Shoot 3 sheets at this setting.

Now open the lens to f/16, and replace the label with the one which reads "TMY 200". Expose another 3 sheets.

So far, we have made 3 sets: One at the manufacturer's recommended speed, another underexposed by 1 stop, and another overexposed by 1 stop. If that's enough for you, stop here. If you want to be more rigorous, you can shoot more sets, varying by 1/2 stop, or 2 stops: it's your decision.

We now have 3 sets of shots: one set for each film speed. We want to develop one sheet from each set for a different length of time. If your developer has recommended time of 10 minutes at 70 degrees, then develop one set for the recommended time of 10 minutes, another set for 8 minutes, and another set for 12 minutes. Or, you can try 9,10, and 11.

If you prefer to test more rigorously, then choose 5 different times, placing the recommended time of 10 minutes in the middle. It's up to you.

The trick here, is to keep track of which ones have been developed for how long. That's for you to decide. If you have an Infra Red Viewing Device, you can see things in the darkroom, and that can make life easier, but it's not a requirement. People have gotten along just fine without them for well over a century.

(If you have a cold light source, also known as a diffusion light source, then you shouldn't see any difference between a contact print and an enlargement, but if the enlarger has a condensor head, or a collimated beam, then the difference will be pronounced: high values will be blocked due to the Callier Effect. My mentor Fred Picker demonstrated this conclusively back in the early 1970's, and compelling illustrations are documented in his classic text Zone VI Workshop).

If you scan your negatives, then make sure your monitor is calibrated, and scan your negatives in such a way that the entire range of brightness on the film, is within the range of the scanner. I recommend that the entire curve of the film, occupy 2/3 of the range of the scanner. This gives you 33% to play with, or around 16% at each extreme. In the parlance of the Zone System, it means that you can play with around 1.5 zones at either extreme if you need to.

You can always add contrast in an editing tool, but if the negative is already too contrasty for the scanner, you're out of luck, or you have to resort to multi-scan and merge techniques from the world of digital sensors and their low tolerance for dynamic range. So it's best to live well within their limitations, and away from the extremes, where "noise" and other distortions appear. New article coming soon: Pyrocat 2-Bath compensating formula, which lets you shoot scenes of 14 zones brightness range, effortlessly.

In Photoshop, GIMP, or your other favorite image editor, add a linear adjustment layer so that the black film edge is rendered at 0% brightness, and so that the high values are rendered correctly. Be sure not to clip any values. Do not introduce any curves: just a straight-line adjustment.

Find the image which feels the most like light, throughout the entire range of tonality. You want the shadows to be dark, but still contain sufficient detail. You want the high values to look clean and white, but still have some texture. You want the human to look like a human. You want white paint in the sun to look like white paint in the sun, but not bleached out. Grey socks should look middle grey. That's the film speed/developer combination which we will use for normal lighting, and expect normal results.

You will also find that one of the film speed/developing times looks best for a "minus-one" development time: The shadows will be normal, but the high values will still be one stop too low. Similarly, you will find a combination of film speed and development time that works nicely for "plus-one": the shadows will look normal, but the high values will be a bit too high, by around 1 stop.

With these times, you can handle many lighting situations that arise: high contrast, and low contrast. If you want to perform more testing, you can determine the best times for N-2, N+2, etc.

Be aware that when we under-develop film, we lose some speed in the process. So (to follow our example) you might have to shoot TMY at a speed of 100 when you lower the contrast by 2 stops, IE with N-2 development. In the same way, if you increase the development time enough to expand contrast up to N+2, you may need to shoot TMY at 300 or higher. Everything is... interconnected.

You can use this same technique to compare the results of the same film in different developers, or different films with the same developer. They are not all the same. This is not only true in terms of densitometry and science, but subjectively. Some film/developer combinations are gritty, while others are smooth. Some are harsh, others are silky. Find the ones you like most. You're the artist.

Recommended Reading

Zone VI Workshop by Fred Picker

One Last Recommendation

Get yourself a 1-degree spot meter.

If you want to know why, read those books.