Among pigments of the second class, or the semi-stable, gamboge holds the foremost place, for although not strictly durable in itself, it conduces to the permanence of other colours. Chrome yellows, citron yellow, strontian yellow, and Thwaites' yellow, also belong to this division.
As third class pigments, or the fugitive, must be ranked Mutrie yellow and other lemon cadmiums, the true gallstone, Indian yellow, the lakes, orpiment, Gelbin's yellow, massicot, patent yellow, and turbith mineral.
It must not be forgotten, however, that these three classes are subject to modification. A durable pigment may be so adulterated as to descend to the second or even the third division, while a semi-stable or fugitive colour may be replaced by a permanent or comparatively permanent substitute, as in the case of strontian yellow and gallstone. It should likewise be remembered that pigments are apt to vary in stability according to the mode of their preparation; and that, as there are different degrees of permanence, there are different degrees of fugacity.
[CHAPTER IX.]
ON THE PRIMARY, RED.
Red is the second and intermediate of the primary colours, standing between yellow and blue; and is also in like intermediate relation to white and black, or light and shade. Hence red is pre-eminent among colours, as well as the most positive of all, forming with yellow the secondary orange and its near relatives, scarlet, &c.; and with blue, the secondary purple and its allies, crimson, &c. It gives some degree of warmth to all colours, especially to those which partake of yellow.
Red is the archeus, or principal colour in the tertiary russet; enters subordinately into the two other tertiaries, citrine and olive; goes largely into the composition of the various hues and shades of the semi-neutral marrone or chocolate, and its relations, puce, murrey, morelle, mordore, pompadour, &c.; and is more or less present in browns, grays, and all broken colours. It is likewise the second power in harmonizing and contrasting other colours, as well as in compounding black and all other neutrals, into which it enters in the proportion of five,—to blue, eight,—and yellow, three.
Red is a colour of double power in this respect too; that, in union or connexion with yellow, it becomes hot and advancing; but mixed or combined with blue, cool and retiring. It is, however, more congenial with yellow than with blue, and thence partakes more of the character of the former in its effects of warmth, the influence of light and distance, and action on the eye, by which the power of vision is diminished on viewing this colour in a strong light. On the other hand, red appears to deepen in colour rapidly in a declining light as night comes on, or in shade. These qualities of red give it great importance, render it difficult of management, and require it to be generally kept subordinate in painting. It is therefore rarely used unbroken, as the ruling or predominating colour, or for toning a picture; on which account it will always seem detached or insulated, unless repeated and subordinated. Hence Nature is sparing with her red, employing it with as much reserve in the decoration of her works as she is profuse in lavishing green upon them. This latter is of all colours the most soothing to the eye, and the true contrasting or harmonizing equivalent of red, in the proportional quantity of eleven to five, according to surface or intensity: being, when the red inclines to scarlet or orange, a blue-green; and when it tends to crimson or purple, a yellow-green.
Red breaks and diffuses with white with peculiar loveliness. It is discordant when standing with orange only, requiring to be joined or accompanied by their proper contrast, to resolve or harmonize the dissonance. In landscapes, &c., abounding with hues allied to green, a red object properly placed as regards light, shade, or distance, conduces wonderfully to the life, beauty, harmony, and connexion of the colouring. Red is, indeed, the chief element of beauty in floral nature, the prime ornament of the green garb of the vegetal kingdom.