Exercise 27 – Colours into tones in black and white

Introduction:

This exercise is mainly to look into the affects of coloured filters. These filters can be used in colour photography, but have a more profound affect when used on black and white images.

By placing a filter over the lens you can dramatically change the tone so a colour becomes darker or lighter grey. By using a red filter as an example, you can make a dramatic  blue sky. Filters allow certain wavelengths of light through and block others from reaching the film. Filters will let through their own colour so the grey tone of subjects with the same colour as the filter will be lighter and the tones of subjects with contrasting colours will become darker.

For the exercise we are to take a picture which includes red, green, blue and yellow. Once taken the image is to be converted into black and white, then adjusted using each of the coloured filters to see the affect they have on the relative colours and tones. We are also told to place a ‘white balance card’ for reference into the frame.

The most common filters used in black & white photography are, Yellow, Orange, Red, Blue and Green, and work by blocking certain wavelengths. When converting to black and white the mid tones are brought to approx. 18% grey.

(click any image to enlarge)

Process:

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Standard image.

Basic colour

This is a basic colour photo taken straight from the camera. No adjustments have been made in post software except white balance.

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Standard black and white conversation. 

Basic black and white conversion

This is a standard black and white conversion uploaded into Lightroom 5. No other adjustments have been made. Although black and white the tones of the varying colours in the fruit can be clearly defined .

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Blue filter adjustment.

Blue Filter

The blue filter has lightened the blue lunch box covering, and slightly lightened the red apples. No other colours or tones are affected.

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Green filter adjustment.

Green Filter

As expected only the wavelengths from the green grapes have been allowed to pass through, making them lighter.

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Red filter adjustment.

Red Filter

The apples have lightened due to the red filter.  In Lightroom I had to bring down the adjustment slightly to prevent the tonal range of the apples burning out.

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Yellow filter adjustment.

Yellow Filter

The yellow filter has made the tones of the bananas a lot lighter, with an increase in tonal adjustment to the grapes slightly also. Again I had to be careful not to over adjust the conversation and burn out the adjusted tonal area.

Conclusion:

When using filters for creating various tones in black and white, here are examples of what filter best suits what purpose;

Yellow: Can be used to slightly change the tones in a blue sky to make them darker. Some photographers even use this type of filter as a lens protector, as it only has a very slight effect.

Orange: Used to lighten reds so it’s favoured by portrait photographers who use it to reduce freckles and skin blemishes. Architectural photographers also find it’s affect on bricks, pavements and certain stone.

Red: Used mostly for contrasty results with tones being dramatically affected. Can be used as an alternative to the true infrared filter and most popular filter for landscapes.

Green: This filter can help differentiate between foliage making the whole scene come to life. Will lighten the blues in skies.

Blue: Hardly used for black and white.

The example photos above show fairly clearly how certain coloured filters change the tones within black and white. The invent of digital has made this process far more easy for adjustments, as opposed to the film days when all filters had to be manually placed in front of the lens and affects only seen after wet processing back in the dark room.