A system developed by the great landscape photographer Ansel Adams for measuring the light levels throughout a scene and allocating them to ten brightness ‘zones’. The idea was to develop the film to a specific level of contrast that captured the full range of tones and make appropriate artistic interpretations with dodging and burning during the print-making process. It worked well with the very exposure tolerant sheet films of the day, where each negative was processed individually, but it’s mostly of academic interest today since digital sensors don’t offer this extended exposure latitude.
Black and white photography
Black and white photography is still very popular, particularly amongst 'art' photographers. You might imagine that colour photography, offering more information about the world than black and white, would be innately superior. But that's not how it works. Black and white has a graphic quality that makes it easier to dissociate the subject matter from the visual appearance of the picture. In other words, people are more likely to appreciate the picture for its composition and its effect than they are to look at it literally and ask you why you took a picture of that particular subject. Anyhow, here's a selection of articles about black and white photography which will explain a little more about the technical side.
Adding a coloured tone to black and white pictures to add depth or atmosphere. The most famous is sepia toning, so often used for Victorian portraits. These days most people simulate toning effects digitally using colour controls and effects filters.
Tonality is a software tool for creating a wide variety of black and white image effects but also includes some colour processes too. It comes with a wide range of preset effects, each of which can be adjusted using manual controls. You can also create and save effects of your own.
A more complex type of toning where two colours are used not one – shadows are tinted with one tone and highlights with another. The results can be very effective, though it’s not always easy to find good-looking toning combinations and split toning doesn’t work with all images.
An interesting localised contrast adjustment in Silver Efex Pro, part of the Nik Collection. Positive values give images increased contrast but with a dark ‘glow’ effect around objects that can be very effective as a ‘look’. Negative values brighten shadows and dim down highlights and can be a useful pseudo-HDR tool – though you will see that same ‘glow’ effect if you push the slider too far.