To see in Black and White

07th November 2012
One of the first difficulties in taking Black and White photographs is how to visualise the scene as different shades of grey. For those who are used to working in colour, it is difficult to remove the colour one naturally sees and interpret the scene, but with practice it is possible to train the eye to think Black and White.

Having achieved this, life becomes easier and the production of striking Black and White images is made that much easier.

To get a basic understanding of this you must think in grey tones, and how the data is transmitted to the camera sensor and what is actually happening when you press the shutter. Ansel Adams and his colleagues devised a way of precise control over exposure, which they called the Zone System.

This was assuming that the camera, film and developing of the negative where all calibrated correctly. This then allowed to determine where the tonal range would fall within the image, and gave them the ability to set a mood for the picture.

As an example, imagine a scene with wonderful fluffy white clouds against a blue sky. If you were to take an average reflected meter reading the whole image would be just another sky and cloud picture with no feel or drama to it which may be OK in colour but it may not be what we are aiming for in a Black and White photograph.

Sometimes we need to make the image more strong and powerful by adding drama, which can be accomplished using exposure control.

I will not explain to deeply about the Zone system as this was primarily devised for film, the development of negatives was an integral part of the system to control negative density by altering development times to suit the lighting conditions and mood of the scene.

Because digital is now the most popular way to capture, that part is missing, but it is still important to understand the basic principles. I will try to explain how to visualize and use exposure as a tool for setting the mood in digital Black and White photography.

First we must understand how all camera meters work whatever the setting be it Auto, Semi Automatic, Programme and Manual modes, the meter will set the correct exposure for a given scene based on thousands of sample exposure scenes within the cameras’ micro-processor.

For your average snapshot this is fine for scenes of average tones in front of the meter, but as soon as the tones are biased towards dark or light that’s when things go wrong, the reason for this is all in built meters are calibrated to produce 18% grey or “middle grey” all other tones are then moved up or down the gray scale to represent the scene in shades of grey.

Look at example 1 below this was a piece of black card I photographed, I set my DSLR in auto mode with no compensation, the black card has turned out mid grey 18% grey, in example 2 , again with the camera set to auto no compensation and the white card has also turned out 18%grey.

You can be seen that the two exposures although different give nearly the same result, middle 18% grey, the camera auto metered for the Black card has given a longer exposure to turn it to 18% grey, and a shorter exposure for the white card has turned that to 18% grey.

In example 3 I have split the image into black and white, the black is better but the white is still greyish, what can be seen from the exposure values on example example 3 is that the camera has tried to average the exposure to come up with the best result it could give, however it is far from satisfactory as the image has turned out what is termed flat with no pure whites or blacks and lacking in tonal contrast.

So what does this tell us, all three exposures are wrong to produce the correct tonal range and contrast, that’s because we have let the camera take control and not the photographer.

Now if we have established what is happening and know the camera will always turn white and black to middle 18% grey we are well on the way to understanding how it will affect our images.

Lets take the examples 1 and 2 above, to turn the black card to a true black the exposure would need to be compensated by at least 3 full stops less and the white card compensated by 3 full stops more, in other words we would have to slide the shades of grey up or down from a given middle grey point.

Look at the grey scale below the background scale is the cameras representation of white, 18% grey, the smaller scale is the exposure compensation required to bring the white card to true white by overriding the cameras settings we have moved the tonal range up the scale.

So lets now see what happens to the card at different compensation settings.

So how does this work in practical terms, take the examples below of a landscape picture, I was aware that auto would not deliver the exposure I wanted, so I bracketed the shots to move the grey scales up and down to reveal better highlight and shadow detail, the examples are all straight from Raw files with no editing applied.

The above exposures give me plenty of tones to play with in Photoshop, example 1 has given a nice middle tonal range, example 2 has moved the grey-scale down to bring out more cloud detail, example 3 has moved the grey-scale up to reveal shadow detail and provide more contrast to work on, it’s worth mentioning that different scenes will require varying amounts of compensation dependent on the intensity of the light.

Below is the finished edited image

To “see” in B&W does take some getting used to, if you can follow the principle of the grey-scale, and try to understand what is happening when you meter with your camera you will be able to produce better B&W images and prints.

Using the grey-scale method the 18% starting point, blacks will be deeper, whites cleaner and a range of mid tones in-between the two, you will also be able to dramatically change the mood of the image which is so important in monochrome by deciding if you want the image to be low-high key, contrast can be reduced or increased.

Even in these high tech times I would suggest using a handheld light meter that can take 1 degree spot readings, the benefit is that whatever you point your meter at its reading at 18% gray and use that as a datum point to adjust your exposure.

10 stop grey scale wedge, zone 5 = 18% grey

One stop over exposure puts zone 5 on to zone 6 and one stop under exposure moves zone 5 to zone 4.

From the above I hope you have a better understanding of how exposure affects the look and mood of a picture and helps you to think and see in grey-scale.


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