Statue in the Oxford University Museum
Roger Bacon was born ca. 1214 near Ilchester in Somerset, England, into a family of landowners. Details and dates of his biography remain quite uncertain with opinions often varying widely. He spent eight years at Oxford University, where he received an advanced degree. It is likely that one of his professors at the time was Robert Grossteste who had an interest in the subject of color. Bacon became a professor at Oxford lecturing on Aristotle and his works, probably in 1233. In the early 1240s, Bacon moved to Paris where he was offered a position as a lecturer at the University of Paris. There, he further studied and taught Aristotle’s works on nature and wrote commentaries on some of them, including those dealing with the subject of color. He also studied in detail the science-related writings of the Islamic scholars Alhazen, Avicenna, and Averroes (ten to twelfth centuries). Either in Paris or after his return to Oxford, he became a Franciscan friar. Bacon returned to Oxford circa 1247 where he further informed himself on the works of Grosseteste and his ideas about science.
The subjects of ancient Greek philosophy and the sciences were not at the time generally approved by the Catholic Church, and Bacon was for a time confined or even imprisoned for teaching subjects not considered to be doctrinal. Circa 1255, he made the acquaintance of Cardinal Guy le Gros de Foulques, who later became Pope Clement IV and who secretly supported him. Bacon wrote several works that he submitted to the pope for his approval including the Opus majus (major work, an 840-page effort to present the knowledge about the world of his time, submitted in 1267 [1], the Opus minus (less important work) and an Opus tertium. Pope Clement died in 1268 with Bacon thereby losing his protector. Bacon lived out his remaining years at the Franciscan House in Oxford. He is believed to have died in 1294. In addition to the three mentioned works, he was the author of many more texts, some discovered much later. He is considered to be an important early force pushing for scientific investigation [2].
14.1 Bacon and Color
Bacon’s views on color, originally based fully on Aristotle and the Islamic scholars, developed over his lifetime, influenced by Grosseteste and his views about science. At the time, the most influential view about color in Western civilization was that of Aristotle, with his five hue species arranged between white and black, species thought to be generated by mixtures of white and black. Bacon became influenced by the late (~second century CE) Greek author Porphyry and his “predicables,” a system of classification based on ideas of Aristotle [3]. The five related classes are (1) genus, (2) species, (3) difference, (4) property, and (5) accident. Bacon applied these to colors: He decided that there are five genera: albedo (whiteness), glaucitas (yellowness), rubedo (redness), viriditas (blue–greenness or grueness) and nigredo (blackness). On the next level, the species, there are the colors that represent these genera: white, yellow, red, blue–green, and black. Mixing the principal species results in differences, such as orange and purple, “composite colors” as he also described them. It is not clear what, for Bacon, represented the class of property but there are hints that he thought along the lines of a concept now expressed as colorfulness. Accidentally, he used to designate different levels of lightness and darkness of colors. Thus, he revised Aristotle’s system in substantial ways [4]. In each of the five genera, Bacon included a number of typical color names as represented by objects or lights, most of them in the genus viriditas ranging from viridis (green) to azure (blue–green) and further to caeruleus (sky blue) and venetius (navy blue). Bacon explicitly rejected Aristotle’s idea of chromatic colors being the result of different mixture ratios of white and black [4].
The idea of three primary chromatic colors had already been introduced in Chalcidius’ fourth century CE translation with commentary of Plato’s Timaeus [5]. However, the text was largely lost and not referred to by Bacon. Three primary chromatic colors became a standard point of view in the sixteenth century as expressed, for example, by Camillo Leonardi in 1502 [6] and Filippo Mocenigo in 1581 [7]. The concept was described and graphically expressed by Franciscus Aguilonius in 1613, as described in Chap. 4 [8].