Robert Grosseteste's colours

TL;DR

This paper translates and discusses Grosseteste's medieval treatise on colours, exploring early theories of light and color that influenced scientific understanding until Newton's prism experiments.

Contribution

It provides a translation and analysis of Grosseteste's De Colore, highlighting early concepts of color and light that predate modern optics.

Findings

Two methods of counting colours: infinite tones and seven colours.

Colours created by purity or impurity of transparent media.

Medieval color theory influenced later scientific developments.

Abstract

Here I am proposing a translation and discussion of the De Colore, one of the short scientific treatises written by Robert Grosseteste. In this very short treatise of the mid-1220s, Grosseteste continued the discussion on light and colours he started in the De Iride. He describes two manners of counting colours: one gives an infinity of tones, the other counts seven colours. In both cases, colours are created by the purity or impurity of the transparent medium when light is passing through it. This medieval framework survived until Newton's experiments with prisms.