The importance of controlled lighting for colour matching

Ever since artists began to paint on canvas rather than cave walls they have always preferred to have the light coming from the sky rather than directly from the sun mainly because sunlight can be dazzling. Industrial colourists have extended this preference to north sky light, but this preference is equally based on a problem which the artist never encounters: metamerism. This problem is by no means recent: as long ago as 1896 a dyer described his first encounter with metamerism in the following way:—