post processing - When is black and white likely to enhance an image?

I recently had a play with converting some images to black and white to see how that changed the image. Some baby photos came out particularly well, while others I tried seemed less interesting when in black and white.

I'm wondering what causes things to look more or less interesting in black and white. Are there any subjects which generally look better in black and white? Or are there particular qualities of a photo which might make you think something would look better in black and white?

Things I've thought of from my own playing around:

• Black and white images prevent the eye being distracted by different colour objects, so the eye may be more drawn to the intended subject.


• When the colours are a strong part of the image (maybe in a festival or market), they are unlikely to look better as black and white.

Are there generally accepted criteria (or rules of thumb) or is it a purely subjective judgement?

Here's hoping I'm not going to start a holy war - I'm genuinely interested if there are any rules of thumb for when black and white is likely to be a pleasing transformation.