Our analisis on Donald Judd's work tries to make visible how light that incides and propagates over his pieces -its internal and external surfaces- was conceived by the artist in the same way as the physical structure of these. This dissertation follows the tendency of the recent critical debate that sees a new concept of colour in Donald Judd's work that until some years ago was taken as an orthodox minimalist leader, far away from any appeal to the senses. Our perspective searches for convincing critical and historiographical arguments to point out how, in Donald Judd's work, colour turns into a synonym of material surface. It's inherent, substantive, non-applied and without methaphorical meanings. That's a new kind of colour, objectively liberated from apriorisic values and prejudices, culturally imposed, that must be taken with all intensity, along with daily life.