Black and white goes back to the very origins of photography. Early plates and films had limited sensitivity to longer (red) wavelengths of light and produce a certain interpretation of the subject. Later films had a much more even response to colours (panchromatic) that led to a different ‘look’.

The differing chemistry and manufacturing processes adopted by various manufacturers resulted in different films producing subtly different renditions of the same scene.

It was soon discovered that using coloured filters in front of the lens also altered the image. For example, a red filter cuts out some of the blue light from the sky while still letting through the red component of the white light reflected from clouds. This results in darker skies, which emphasise the clouds.