In this, possibly the oldest system to use the trio of red, yellow and blue, colours are defined within a linear division. Their mixing options can be deduced using bows. «One can see in his achievement the quietness of the monastery, which can permeate into the smallest detail of a work» was Goethe’s comment on the work Franciscus Aguilonius, whom he rated highly. (Detailed text)
Franciscus Aguilonius (1567-1617) «was a Jesuit in Brussels and published his Optics in large format in Antwerp» — as recounted by Goethe in his History of the Theory of Colours, adding: «one can see in his achievement the quietness of the monastery, which can permeate into the smallest detail of a work». We could also add that the origin of the curved bow of his
It is clear that François d’Aguilon — his French name — also conforms fully to the tradition of Aristotle, and he uses the bow as an addition to the classical, linear division to specify the possibilities that arise from mixing colours. It is important to note that in his optics textbook, which appeared between 1606 and 1611, Anguilonius did not merely wish to envisage the painterly «colores concreti», but was more interested in the visible colour qualities which this revealed.
An attempt at transferring musical consonants into the area of colour formed the basis of his scale. To this end, Aguilonius did not concern himself with harmonies, but simply the relationship between the colours. As a physicist, he had introduced the expression «simple colours», meaning any colour from which an infinite number of other colours could arise through mixing. As our illustration shows, there are five of these simple colours, and a further three can be directly composed from these.
«Quinque sunt simplicium colorum species, ac tres compositiae», states the propositio 39 of his work. Between the extreme colours (colores extremi), defined as brightness and darkness — named «albus» and «neger» — come the median colours (colores medi): «flavus — ribeus — caeruleus», thus yellow — red — blue. If, in accordance with their respective bows, in each case two of the simple basic colours are mixed, then «aureus, purpurus and viridis», in other words gold, purple and green will be formed. But Aguilonius explicitly warns against a mixture of all three simple colours, since in this case only a murky grey hue will result — a «corpse-like colour».
Aguilonius is praised by Goethe, since he expresses more clearly than usual «that the colours must be arranged according to the differing ways in which they appear». At the same time, Anguilonius differentiates — in Goethe’s translation — between «true, apparent and intentional colours» which, in his History of Colour Theory, the poet explains in the following way: «The true colours are allocated according to the properties of the bodies, the apparent colours are seen as unexplainable, indeed a divine secret, but yet to a certain degree they are also to be regarded as coincidental.» The intentional colours are still more difficult to substantiate, since, according to this interpretation, they are granted a will and a purpose — indeed a «spiritual nature, due to their delicateness and effect». Goethe devotes an entire chapter to them, which we can here only refer to.
Aguilonius also applies the triple subdivision of colours to their mixtures, and in this respect the above concepts are easier to understand. The intentional mixing («compositio intentionalis») merely involves the superimposition of numerous colours. In addition, Anguilonius also defines the combination of physical dyes («compositio realis»), as well as the distribution of the smallest colour patches («compositio notionalis») which can be perceived by the eye as a mixture, although his diagram does not emphasise this clearly. His bows can certainly not be used in all three cases, since a mixture of yellow and blue light produces not green — as portrayed by Aguilonius and which applies to paints — but white.
As the jargon of the Neo-platonists, amongst whose numbers Aguilonius is counted, would have elegantly stated: «The colour diagram shows the relative position of the simple and composite colours on a scale which determines their respective status through a colour’s participation in light». In his case, in accordance with the added proportions of white and black, all colours also exhibit different grades of intensity.
While working on his optics textbook «Opticorum libri sex», Anguilonius had collaborated with the Dutch painter Paul Rubens, who at that time (1611) was painting Juno and Argus, his famous visual allegory. Included in the picture are a rainbow and a peacock, and many have wondered at the fullness and abundance of their colours. In the second century A.D, the Gnostics had already made the surprising observation that the infinite fullness of colours in the tail of a peacock all emerge from a single white egg, and bestowed upon this the greatest of all mysteries. In our modern age, this has been reduced to a banality. The idea that the potential for all colours is contained in white alone is therefore ancient, and emerges clearly in a 13th century treatise attributable to Albertus Magnus, which states: «Appearing in white are absolutely all the colours which mankind can imagine on the face of this Earth». In 1669, before embarking on the experiments dedicated to this very insight, Isaac Newton purchased the collected works of Albertus Magnus.
Date: The colour diagram appeared in 1613 in a work on optics.
Country of origin: Belgium
Basic colours: Yellow, red and blue appear between white and black
Bibliography: F. Aguilonius, opticorum Libri Sex, Antwerpen 1613; J. W. von Goethe, Geschichte der Farbenlehre, Part 1, Munich, 1963; F. Gerritsen, Entwicklung der Farbenlehre, Göttingen 1984; John Gage, Colour and Culture, Practice and Meaning from Antiquity to Abstraction, Thames and Hudson, 1993 (mention and comment).