ABSTRACT
With a digital image, the effect of colour filters can be fairly accurately approximated using post-production software. Digital sensors respond better to a full spectrum of light and filtering the light reaching the sensor can produce unwanted noise in the image. Channel mixing is one popular way of creating black and white from digital colour. Different proportions of each of the red, green and blue channels that go to create the digital colour image can be mixed to create different monochrome outcomes. Filters that change the whole visible spectrum are suitable for use with both film and digital cameras. Neutral-density filters are made from plain grey glass, resin or polyester and come in a choice of densities. All neutral-density filters cut out light equally across all wavelengths of light. Some filters that were originally intended for use with colour film will also work with black-and-white film.
