Ansel Adams used the word 'pre-visualisation' to describe the act of seeing the finished photograph before you press the shutter. For black and white photography, this means stripping colour from your mental picture of the scene — before you take it — and seeing it in tone only.

This is a learnable skill. It is also a discipline, because colour is the dominant visual mode. We see colour first. We notice a red coat, a yellow bus, a blue sky. In a colour photograph, these elements all play their role. In black and white, none of them exist. What replaces them is contrast: the tonal relationship between light and dark.

The simplest way to develop pre-visualisation is to set your camera to display a black and white live view, even if you are shooting colour files. Many mirrorless cameras allow you to display in JPEG simulation (monochrome) while saving RAW files in colour. You see the world in black and white as you compose, and you can decide on the spot whether the scene works without colour before you commit.

If your camera does not support this, squinting slightly reduces colour saturation and helps you see tonal relationships more clearly.

What to look for: does the scene have enough tonal separation to read without colour? A red coat against a green hedge disappears in black and white — both are mid-tones. That same red coat against a white wall is a strong black-and-white composition. The contrast is tonal, not chromatic.

Watch for: skin tones in portraits. In colour, skin is self-evident. In black and white, dark skin against a dark background becomes a figure-ground problem.

The point: black and white photography is not a post-processing filter. It is a way of seeing, and the seeing must happen before the shutter fires.