ON THE SECONDARY, GREEN.
Green, which occupies the middle station in the natural scale of colours and in relation to light and shade, is the second of the secondary colours. It is composed of the extreme primaries, yellow and blue, and is most perfect in hue when constituted in the proportions of three of yellow to eight of blue of equal intensities; because such a green will exactly neutralize and contrast a perfect red in the ratio of eleven to five, either of space or power. Of all compound colours, green is the most effective, distinct, and striking, causing surprise and delight when first produced by a mixture of blue and yellow, so dissimilar to its constituents does it appear to the untutored eye. Compounded with orange, green converts it into the one extreme tertiary citrine; while mixed with purple, it becomes the other extreme tertiary olive: hence its relations and accordances are more general, and its contrasts more agreeable with all colours, than those of any other individual colour. Accordingly it has been adopted very wisely in nature as the common garb of the vegetal creation. It is, indeed, in every respect a central or medial colour, being the contrast, compensatory in the proportion of eleven to five, of the middle primary red, on the one hand, and of the middle tertiary russet, on the other; while, unlike the other secondaries, all its hues, whether tending to blue or yellow, are of the same denomination.
These attributes of green, which render it so universally effective in contrasting colours, cause it also to become the least useful in compounding them, and the most apt to defile other colours in mixture. Nevertheless it forms valuable semi-neutrals of the olive class with black, for of such subdued tones are those greens by which the more vivid tints of nature are opposed. Accordingly, the various greens of foliage are always more or less semi-neutral in hue. As green is the most general colour of vegetal nature and principal in foliage; so red, its harmonizing colour, with compounds of red, is most general and principal in flowers. Purple flowers are commonly contrasted with centres or variegations of bright yellow, as blue flowers are with like relievings of orange; and there is a prevailing hue, or character, in the green colour of the foliage of almost every plant, by which it is harmonized with the colours of its flowers.
The chief discord of green is blue; and when they approximate or accompany each other, they require to be resolved by the opposition of warm colours. It is in this way that the warmth of distance and the horizon reconciles the azure of the sky with the greenness of a landscape. Its less powerful discord is yellow, which needs to be similarly resolved by a purple-red, or its principles. In tone, green is cool or warm, sedate or gay, either as it inclines to blue or to yellow; yet in its general effects it is cool, calm, temperate, and refreshing. Having little power in reflecting light, it is a retiring colour, and readily subdued by distance: for the same reason, it excites the retina less than most colours, and is cool and grateful to the eye. As a colour individually, green is eminently beautiful and agreeable, but it is more particularly so when contrasted by its compensating colour, red, as it often is in nature, even in the green leaves and young shoots of plants and trees. "The autumn only is called the painter's season," remarks Constable, "from the great richness of the colours of the dead and decaying foliage, and the peculiar tone and beauty of the skies; but the spring has, perhaps, more than an equal claim to his notice and admiration, and from causes not wholly dissimilar,—the great variety of tints and colours of the living foliage, accompanied by their flowers and blossoms. The beautiful and tender hues of the young leaves and buds are rendered more lovely by being contrasted, as they now are, with the sober russet browns of the stems from which they shoot, and which still show the drear remains of the season that is past."
The number of pigments of any colour is in general proportioned to its importance; hence the variety of greens is very great, though the classes of those in common use are not very numerous. Of the three secondaries, green is the colour most often met with, and, consequently, the most often compounded: for this last reason, perhaps, the palette is somewhat deficient in really good original greens—more deficient than there is any necessity for.
CHROME OXIDES.
By numerous methods both wet and dry, oxides of chromium are obtainable pale and deep, bright and subdued, warm and cool, opaque and transparent: sometimes hydrated, in which case they cannot be employed in enamelling; and sometimes anhydrous, when they are admissible therein. But whatever their properties may be, chemical, physical, or artistic, they are all strictly stable. Neither giving nor receiving injury by admixture, equally unaffected by foul gas and exposure to light, air, or damp, these oxides are perfectly unexceptionable in every respect. For the most part they are eligible in water and oil, drying well in the latter vehicle, and requiring in the former much gum. They have long been known as affording pure, natural, and durable tints; but, until within the last few years, have been rather fine than brilliant greens. Lately, however, processes have been devised, yielding them almost as bright, rich, and transparent, as the carmine of cochineal itself.
175. OXIDE OF CHROMIUM,
Opaque Oxide of Chromium, Green Oxide of Chromium, Chrome Oxide, True Chrome Green, Native Green, &c., is found native in an impure state as Chrome Ochre, but is always artificially prepared for artistic use. Obtained anhydrous by dry modes, this is the only chrome oxide available in enamelling, and is the one seen on superior porcelain. It is a cold, sober sage green, deep-toned, opaque, and, although dull, agreeable to the eye. Its tints with white are peculiarly delicate and pleasing, possessing a silvery luminous quality, and giving the effect of atmosphere. Being very dense and powerful, it must be employed with care to avoid heaviness, and is preferably diluted with a large quantity of white, or compounded with transparent yellow. In the hands of a master, this gray-green furnishes lustrous hues with brown pink, Italian pink, and Indian yellow; three beautiful but fugitive pigments, of which the two last may be replaced by aureolin. Of this Mr. Penley observes, "as adapted for the colouring of foliage and herbage, it is impossible to say too much in its praise. It imparts the vividness and freshness of nature to every colour with which it is combined;" and he brackets oxide of chromium with aureolin as a compound hue "extremely useful." In flat tints, the oxide sometimes does not wash well in water.