Often when we are shooting with a coloured film, we come across a blue or red caste on your image. This may be due to incorrect white balance or when the lighting is not according to the standard day light. Different lights have different temperatures and it is this very temperature that your camera senses to get the right tonal values for all the colours in that light. So if you are shooting in daylight (5600k) with a film that is balanced for tungsten light (3200k), then you would see a bluish cast in your image. For instance if you see the two images below, the first picture was taken without a filter and with a film balanced for tungsten light, so there is a bluish cast in the image. Now if you use a blue colour corrector filter like 85B Cokin P 030, then the caste goes away and the natural colour of the picture is retained. Colour corrector filters are used to correct any colour errors that are arising in your frame due to a change in the colour temperature of the light.

Often when you shoot indoors with a daylight balanced film, then you come across an orange cast in your image which again can be corrected through a colour corrector filter. In this case if you use an orange colour corrector filter, then it will absorb the orange cast and give a natural feel to your frame. Available in various categories and kinds, colour corrector filter range from light warming filters, light cooling filters to minus colour temperature filters which reduce a certain colour caste and plus colour filters which enhance a particular colour cast.