Vacuum Tubes and the Zone System

Vacuum tubes (triodes) inside an old radio.

The Maker Faire in New York City had a lot of new stuff, but there was a lot of good old stuff there, too. I found some vintage radio equipment that was on display and got in close to take this photo.

I took the photo with a Nikon Coolpix 210. Because the tubes are so reflective, you can actually see me if you look close enough.  I’m wearing a brown denim jacket. There were a couple of “floating heads” in the tubes — other reflections of just parts of people’s faces, so I used the rubber stamp tool to get rid of them. It looked weird and I have no idea who those people were. I converted the image to black-and-white using the Topaz filter plug-ins.

I’m getting a lot of mileage out of those filters because I used to do black-and-white darkroom photography, and I still tend to compose my images based on tonal values instead of just the colors in the scene. If you’ve never heard of Ansel Adams’s Zone System, take a look at this article, The Digital Zone System, on the Outdoor Photographer website. I learned the system using black-and-white film, but the principles are just as valid with color film or digital images.

One caveat that I’d like to offer is that if you intend to print your images, you might have trouble with any part of your image that’s in Zones 1 to 3. This has to do with the physics of ink on paper: paper absorbs ink, and even tiny amounts of ink can spread through the paper fibers like wildfire, particularly if you are using an uncoated paper. Any part of your printed picture that has lots of dark color can turn out muddy because there’s simply too much ink for the paper to absorb. When this happens, your image loses detail in the darker areas.

When I worked in the printing industry, we avoided this by editing black-and-white photos in Photoshop and making sure that the darkest part of the image didn’t go beyond 92% to 95% black. It gets worse with color photos, because four colors of ink are used for full-color printing: cyan, magenta, yellow, and black. Instead of percentage of black, we used a total-ink formula of about 320 (100 percent of each ink would equal 400).

As far as Zone 0, or paper white, that part of your image has absolutely no detail. Or, no dot, as printers would say. Another term for it is “specular white.” Try to keep bright reflections from metal and other similar small parts of your image at Zone 0. Too much Zone 0, and your image becomes a zero. No joke.

This vacuum-tube picture probably ranges from Zone 2 to Zone 8. The solid black border is Zone 0. Nothing in the image is bright enough to reach Zones 9 or 10. The compressed tonal range adds to the antique appearance of the image, as though it has faded over time. So, the Zone System as its broadest gives you a dynamic image, but purposely compressing the range gives you other effects. It’s up to your creative muse which way you want your work to go, but definitely add the Zone System to your toolbox.

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