Monochrome just means one colour. The term is often used with black and white, but it also includes other single-colour photography techniques, like sepia, and cyanotype. I’ve even seen red and gold used beautifully.
Colour and monochrome have very different presentation. The beauty, and challenge, of monochrome photography is to use the absence of colour to bring out the message of an image more clearly.
To do this intentionally requires thought and planning, like any good image.
Why do some images look better in monochrome?
Texture and contrast information comes from light and dark. This is what we are left with when we remove colour. In a full-colour image, the colour can work with the tone and texture, or it can fight against them. In a beautiful colour image, everything is working together. The colours in a sunset often draw your eye in the same way as the tone and contrast – you won’t see many B&W sunset photographs because of this harmony.
Where you will see monochrome (or reduced colour) used is when there is something else in the scene – a solitary hut or figure that would be lost in the golds and yellows of the sunset, but is clearly part of the story in black and white.
With noir photography (think 1920’s gangsters), monochrome often looks best. A colourful silk tie, bright blue suit, or yellow dress, might not sit well with a gritty, mob theme. This is a case where the mood of an image conflicts with its colour.
Nostalgia is another common use for monochrome. Many subjects are often seen in black and white, because that’s what people had at the time. A similarly themed image in colour may not have that same feeling of yesteryear.
An image shot intentionally to be seen in black and white will almost always look better than an image that is run through filters to see what looks best. That said, intuitive photographers may make colour images, with strong tone and contrast, without realising they have a perfect candidate for a monochrome image.
With practice, you can see in your mind what an image looks like in monochrome, without having to make an exposure. This same skill can help you identify a monochrome gem in your existing catalogue of images. Looking back at your previous work, and testing it in monochrome, can help you identify those scenes that work in black and white. Who knows? You might be a black and white photographer is disguise, and at least you will have some fun with filters.