Why do black and white photographers use such brightly coloured filters?
Colour filters can achieve a variety of effects in black and white photography. They work by passing light that s the same colour as the filter and blocking much of the light that s the complementary colour. For example, a red filter lets lots of red light through but blocks blues and greens. What does this do on black and white film? Well, such colour filters have the effect of brightening areas in a photo of their own colour and darkening areas of their complementary colours. So, our red filter will make a red T-shirt look almost white and a blue sky look dark grey or almost black. It s for this latter purpose that red filters are commonly used in black and white photography – they can be used to darken skies dramatically and smooth skin tones of lighter-skinned people. This effect of sky darkening is particularly useful when there are clouds. Clouds and sky are often the same brightness on black and white film, which means that clouds can end up disappearing in the final photo. By u
