Black and White Filters
A coloured filter used in Black and White photography will lighten any colour that is similar to its own, and darken other colours. A red filter for instance, will make a red post box appear almost white and blue sky as almost black as the relevant colours are either transmitted or absorbed. Green filters are popular for lightening foliage or grass and blue filters are often used to enhance skin tones and texture in portraiture, as they will darken pinks and reds. Pale colours have a subtle effect whereas dark hues effect the image dramatically.
