In multistage or multicolour printing, one of the printing phases may occasionally be omitted, causing one or more colours to be missing from the stamp. Such errors are usually the result of human oversight or a production fault.
Among the best-known Hungarian examples are the Nagymánya and Moon Rocket major errors.
Warning: some stamp inks may fade substantially over the decades or even disappear partly, especially after prolonged exposure to strong light or sunlight. A well-known example is the ink used for the central design of the 1921–1925 Crowned Madonna issue, which may be heavily faded or absent on some stamps. This is not a genuine missing-colour error.
Certain colour impressions, especially gold and silver, can also be removed comparatively easily from a stamp. Forgers may exploit this, so valuable missing-colour varieties should be examined carefully and, where appropriate, accompanied by an expert opinion.
