Thin-film interference pattern shown by bubble film, 1980-2000.
© Science Museum / Science & Society Picture Library
White light contains a range of different colours - wavelengths of electromagnetic radiation - that the human eye cannot distinguish. Waves can 'interfere' with one another, and if two waves are out of place, so that the crest of one coincides with the trough of the other, they cancel one another out. In thin bubble films, light reflected from one surface of the film interferes with light reflected from the other, resulting in a range of colourful effects known as an interference pattern, or fringe.