This section is from the book "A Treatise On Architecture And Building Construction Vol4: Plumbing And Gas-Fitting, Heating And Ventilation, Painting And Decorating, Estimating And Calculating Quantities", by The Colliery Engineer Co. Also available from Amazon: A Treatise On Architecture And Building Construction.
52. Purple, the third and last of the secondary colors, is, as already stated, composed of red and blue, in the proportion of five of the former to eight of the latter. This constitutes a perfect purple, one of such hue as will best contrast with and neutralize a perfect yellow, in the proportions of thirteen to three, either of surface or intensity. It forms, when mixed with the co-secondary color, green, the tertiary color, olive; and when mixed with the remaining secondary color, orange, constitutes, in like manner, the tertiary color, russet. The coolest of the three secondary colors, it is nearest to black in respect to shade, in which regard, as well as in its quality of never being a warm color, it also resembles blue. Purple partakes, in other respects, of the properties of blue, for blue is its governing tint. To the eye, purple is a most retiring color, reflecting little light and declining rapidly in power, in proportion to the distance at which it is viewed. It also recedes in a declining light, wherein it proves itself the most retiring of positive colors.
Purple is, next to green, the most pleasing of the consonant colors. As much, perhaps, from its rareness in a pure state, as from its individual beauty, it has long been celebrated as a princely and imperial color. Purple, when inclining to red, takes the name of crimson. Indicative of other shades of purple are the names violet, lilac, etc. Purple may be made by the admixture of ultramarine blue and vermilion, or of Prussian blue and lake, with varied proportions of white-that pigment required to impart a blue tendency predominating. With increased additions of white, the various tints of lavender, lilac, etc. are produced.