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Black and White Photography (part 3)
In part 2, we covered the process of converting from colour to black & white. However once you've done this, you may still want to carry out some further enhancements. Many of the tools available to colour photographs are also available to black and white such as levels and curves. However since black and white is far more dependent on contrast and tone than a colour image, you may find that you will want to push these effects further (for example using much steeper 'S' curves when increasing the contrast in your image.
However two of the most useful tools for black and white manipulation are the dodge and burn tools.
Dodging and Burning
The technique of dodging and burning come from the days of traditional darkroom developing (see box below). Dodging refers to the process of lightening specific parts of the image, whereas burning is darkening parts of the photo.
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A History of Dodging and Burning
In traditional darkroom photographic developing, an enlarger is used to pass light through the film negative and onto the light-sensitive paper below. By exposing different parts of the paper for different lengths of time, the photographer is able to make some areas brighter and other areas darker.
To lighten part of the image, the photographer would need to reduce the amount of time that part of the paper was exposed to the light. This would be achieved by holding a bit of card (or even just a hand) between the light and the paper, so that a shadow is cast onto the paper. This process was known as dodging.
The areas of the image that were not covered would have received a longer exposure time and are said to have been 'burned'. |
If the whole image is over or underexposed, you are best to try and correct this using tools like 'Levels' or 'Curves', or the exposure slider in the Raw conversion (if applicable). However if only small parts of the image are under or over exposed, you can use the dodge and burn tools respectively to correct it.
The dodge and burn tools are what are known as brush based tools - i.e. they lighten or darken the image when you move the brush over parts of the image. You can specify the brush size, edge-hardness and exposure/opacity (how quickly the effect is applied for each stroke), and then use freehand strokes to gradually lighten or darken the image until you are happy with it.
Both tools can usually be set to apply the effect to a specific part of the tonal range. For example:
Applying the dodge tool to highlights: brightens the already light areas, increases contrast, adds a little 'sparkle' to the image. This is commonly used to add a finishing touch to an image.
Applying the dodge tool to midtones: generally brightens that part of the image.
Applying the dodge tool to shadows: brings out detail that might be lost in the shadow areas of the image but can also decrease the overall contrast of the image.
Applying the burn tool to highlights: not generally very useful – decreases contrast. Can sometimes be used to make skies a little more dramatic but use carefully.
Applying the burn tool to midtones: generally darkens that part of the image.
Applying the burn tool to shadows: darkens the already dark areas, increases contrast. Can be used to great effect to add more mood to an image
Dodging highlights and burning shadows in the same areas can have a very dramatic effect on the contrast in that area and is useful in black and white images that look a little flat and where applying such an effect to the whole image would make the image look overprocessed.
Useful Tip: keep the exposure or opacity value very low (about 3% or so). It is better the apply the effect slowing with a series of strokes rather than applying it quickly with just one or two strokes.
An alternative dodge and burn method
The dodge and burn tools are not always the best way to dodge and burn. Despite being designed specifically for the task there are non-destructive ways of achieving some of the same ends.
A popular method is to use a layer with the blending mode set as "overlay". To do this, create a new layer in Photoshop, press Alt and click the new layer icon. Name your layer then select the blending mode as "overlay" then tick "fill with overlay-neutral color (50% gray).
Once you have created this layer you can paint on it to selectively lighten or darken parts of the image. Use a soft edge brush with a low opacity (3% or 4%) and where you want to darken, paint black and to lighten paint white.
The advantage of this method over the dodge and burn tools is that it's all done on a separate layer and can easily be deleted or changed later. In fact you can have multiple layers such as separate dodge and burn layers. With the dodge and burn tools it is harder (and sometimes impossible) to fix or change later in editing.
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