The first coherent explanation of color was given by Aristotle in Book III of the Meteorologica. In an explanation of rainbow formation, Aristotle argued that colors are produced by different combinations of darkness and lightness. […] Here, we only have room to mention two conclusions from his work that are particularly important to the present article:
(i) All colors can be ordered in a linear series from white to black. This series is described in De sensu 4, 442a20-25, and is repeated here in Figure 1. This series may have been meant to be essentially an ordering of colors according to their lightness. But its order does not agree with the order of rainbow colors. Therefore, when describing the rainbow in the Meteorologica, Aristotle had to change the series slightly: blue is not mentioned, yellow is not considered to be a real color but just a visual illusion due to contrast and violet and leek-green have changed position.
(ii) By mixing white and black, all colors can be produced.
The first conclusion implies, when restated in modern terminology, a one-dimensional color space. Modern science has shown that color is an essentially three-dimensional phenomenon.
- Eric Kirchner and Mohammad Bagheri (“Color Theory in Medieval Islamic Lapidaries: Nīshābūrī, Tūsī, and Kāshānī”, page 2)
In his Kitāb al-Shifā’ (later translated into Latin as Liber de Anima, abbreviated as DA in the translation below) the whole of Chapter 4 in section 3 is devoted to colors. There we read:
“Moreover, if whiteness does not exist without light and blackness not in ways already discussed, then whiteness and blackness cannot only be joined in one manner. A manifestation of this is the fact that white gradually passes to black by three paths. The first is via pale (DA: light yellow-green) and its progression is pure: it will indeed be of pure progression, at first it progresses to pale (DA: light yellow-green), from there to grey (DA: yellow-green), and continuing in this manner until black is obtained, because thus proceeding to its limit, it does not veer from gradually stretching towards blackness, until it becomes pure black. There is also another path proceeding [from whiteness] toward red (DA: light red), from there to red brown (DA: red), thereafter to black. The third path is the one going to green (DA: blue-greenness), from there to indigo, thereafter to blackness. And in these ways not all color diversity can exist, neither can they be the source of the diversity of [Aristotelian] median colors.”
This shows that Ibn Sīnā rejected the second Aristotelian conclusion mentioned above that all ‘intermediate colors’ can be produced by mixing black and white. But [it] is also clear that Ibn Sīnā did not agree with the first Aristotelian conclusion either. The color ordering proposed by Ibn Sīnā is necessarily a two-dimensional one, as illustrated in Figure 2.
- Ibid, pages 3-4.
In the Islamic world, Ibn Sīnā’s new color order was elaborated further by the director of the astronomical observatory in Maragha, Nasīr al-Dīn Tūsī (d. 1274). In an answer to questions about Ibn Sīnā’s color theory raised by one of his staff members, Najm al-Dīn al-Kātibī, Tūsī wrote:
“Regarding the production of colors from black and white there are numerous paths, from which one gradually walks from white to black. The path through yellow belongs there: First by the mixing of dense and fire, both in small amount, the straw-yellow is produced, then the lemon-yellow, then the saffron-yellow, then the orange-yellow, then the grenade-yellow, then in it the tendency towards black increases, according to the increase in the number of dense particles and the decrease of fire, until it becomes black. Another path goes through red. First it becomes rosy then like evening-red, then blood-colored, then purple, then violet, violet-colored. One path goes through green. It becomes pistachio-colored, then leek-colored, then verdigris-colored, then eggplant-colored (bādinjānī), then naphta-colored. One path goes through blue. It becomes sky-blue, then Turkish blue, then lazur blue (lāzwardī), then indigo blue, then like kohl. One path goes through turbidity/dirt. It becomes grey, then darkish/dirt-colored, then dark etc.
These all occur according to the differences of particles in transparency, opacity (density), light and darkness. Now and then one sees a color together with another, and a different color is produced, such as green from yellow and blue, verdigris from green and white. There are infinitely many of such arrangements, and some are often found in small particles of plants and animals. Anyone who observes them is surprised by their number.”
So, instead of the three paths leading from white to black, as described by Ibn Sīnā, Tūsī found that there are no less than five such paths. They pass through yellow, red, green, blue, and grey. Thus, a new color ordering results that can be illustrated as in Figure 3.
- Ibid, pages 4-5.