When Black and White?

I started by titling this ‘Why Black and White?’, then soon realised that the more important question is when. It’s no secret that digital shooting has opened up new possibilities for black and white photography because of now-sophisticated channel control. What previously took strongly coloured filters in front of the lens at the time of shooting is now simple, controllable and much more precise at the time of processing. And it’s this last point – the moment at which we can choose black and white over colour that is making the biggest difference.

Either colour or black and white works for this image of a remote Khmer ruin, but for me the sense of form and volume in the face tipped the balance.

But first, let me recap on the differences between shooting black and white on film and digitally. Black and white film contains light-sensitive silver halide crystals suspended in a gelatin emulsion on a polymer substrate. The precise sequence of events that follows the exposure of film to light is complex. First, light releases photoelectrons and these combine with silver ions to produce silver atoms, which form around small specks of impurity scattered throughout each silver halide crystal. At this stage, there is still no visible image on the film, and it takes a chemical developer to produce it. Development blackens the parts of the emulsion that were exposed to light, by reducing the grains of silver halide to metallic silver, which is dark. Each grain is either developed – that is, blackened – or not; there are no halfway stages of grey. The final result, with a range of tones in the negative, is due to the huge number of developed grains in any small part of the film.

A sensor, too, records light in monochrome, but like tri-pack colour film has a way of filtering the light into three channels. This is the Bayer array bonded to the front of the sensor (apart from the quite different but little-used Foveon method) – a checquerboard pattern of red, green and blue filters, each over one photo-site. This means that the accuracy of the colour information is much less than the tonal information, as each pixel is filtered one of three ways, but practically it hardly matters. The colours are extrapolated and filled in, and in any case, as is known from neuroscience, our eyes and brain have quite low colour resolution and are easily satisfied. Now, while it may seem a roundabout way to create a black and white image from a colour file, going back from three channels to one, one wonderful advantage is that the three colour channels can be used during processing to turn any colour in the image into almost any tone of grey, from black to white. I’ll deal with this in more technical detail in the Techniques pages here on the site (and I also have a new book coming out, The Complete Guide to Black and White Digital Photography).

A similar, but less precise technique can be used with film, by placing a filter of one strong colour in front of the lens. A red filter, for example, passes red light and blocks blue and green, rendering blue skies very dark. And so on. But doing this accurately meant having experience, not least in compensating with the exposure, and was always a little cumbersome.

But the most important difference, it seems to me, is the matter of choice and timing. For those photographers not committed fully to either colour or black and white, it used to involve a decision right from the start – to go out and shoot one or the other. The alternative was a second camera, so that you had both film types loaded. Now, digitally, black and white is a processing choice, so that you don’t necessarily have to choose earlier when shooting.

Certainly, many photographers – maybe even the majority of those working in black and white – think, compose and expose in monochrome, which you might argue is the way it should be. Conceiving a shot for how it will appear, which in this case means black and white, has clear advantages over being indecisive. But indecision might just be the new order for this area of photography. Until now, it has almost been unquestioned that to shoot well in black and white you must first set your mind to black and white. Ansel Adams, never short of an opinion in these things, wrote that “A technique difficult for any photographer to master is the visualization of various colors in terms of black-and-white tonalities”, adding that “Values and colors should be first recognized as they are in relation to monotone values, rather than for their emotional qualities.” Eliot Porter commented that “When Ansel Adams photographs something, he sees it as a black and white image right away and so he photographs it that way”, while Edward Weston for his part “spent years trying to avoid” the temptations of colourful scenes.

I wonder, however, if this might be a little outdated. In so many other areas of photography, there is room for surprise discoveries (such as Garry Winogrand famously saying, “I photograph to see what the world looks like in photographs.” – deciding later whether or not a shot works or delivers some interesting quality. Perhaps here too. What’s intrinsically wrong with sitting back later in front of the raw files and experimenting with colour-or-not? Not much that I can think of, other than that it doesn’t follow the old ideals. Which might not carry so much weight as they once did. This is why digital shooting is in the process of profoundly altering the rôle of black and white in photography.

So how would you make these choices, given that they are easy enough and can be made for any image, at your leisure? It is now less a case of ‘I prefer black and white to colour’ than ‘this particular image might work better in black and white than in colour’. Well, it would be foolish to search for hard and fast rules, as ultimately this is a personal choice. But here, briefly, are some conditions that might tip you towards processing in black and white:

• When one or more colours in the image distract from the main subject (such as a vivid colour in the background that is irrelevant to your idea of what the image is about).
• Images with a strong, formal graphic structure, in which shape and line dominate.
• Images which show strong rendering of volume through lighting.
• When texture dominates.
• When you want to exaggerate the tonal range, such as by going for very high contrast or for a marked low key or high key. Each of these styles can be taken further without losing integrity in black and white than they can in colour.
• When the lighting doesn’t seem to work in colour, such as too harsh (strong midday sun) or too flat.

All of this seems to me to bring colour and black and white closer together. Not only do they have a common starting point -the raw file – but there is also an infinite shade of colourfulness possible. You could call this a continuum of colour, varying in saturation from vivid (see my earlier Over-processing piece) to monochrome. Given this, I feel inclined myself more and more to combine colour and black and white imagery in, for instance, a book. My new book, which will be out next year, on the Tea Horse Road through western China and Tibet, is a case in point. Some of the images simply seem to work better in black and white than they do in colour, so I process them that way, and run them in the layouts with the colour images.

Some examples of images that I thought worked better in black-and-white than in colour…

The colours in this scene of yaks being driven down a hillside are nothing special, and what I wanted was both a strong sense of the dust being kicked up and the flow of the movement. Processing in black and white allowed selective high contrast to bring it alive.

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The man’s strong, angular face and the gesture of his hand holding the cigarette were what drew me to shoot. Any colours are a distraction, and in particular the out-of-focus background at right.

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First, the rock here in the Red Sea Hills is strking and the shot is very much about form. Second, processing in black and white can bring out a powerful contrast with the sky — the equivalent of shooting with a red filter but with much more control.

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The scene and the situation were perfect, but the midday light harsh and unspecial. There was no question of waiting for better light later in the day, as the mule train was crossing right now. Black and white suffers hardly at all from this kind of lighting, with the added bonus that the channels could be mixed to balance the tones of the water and the greenery in any way wanted.

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Tags: Ansel Adams, black & white, digital, Eliot Porter, silver halide