In the i8th century, we come to the earliest use of ivory as a suitable material on which to paint portrait miniatures. This provided miniature painters, especially those of France, with exactly the most suitable material upon which to use the newly discovered transparent colours. The establishment of the Royal Academy (1768) was largely responsible, in England, for the popularity of the miniature painting on ivory.
Richard Cosway (1742-1821) is usually regarded as the prin cipal English exponent of the art, so much so that for a long time when little was known of other artists, miniatures on ivory spe cially well painted were invariably attributed to him. His works are brilliant and of considerable beauty, his dexterity being so great that the portrait, to use the words of a well known critic, looks as if it was blown on to the ivory, and was gently resting there. With all their beauty, however, Cosway's miniatures possess many faults in draughtsmanship, and these were exaggerated by one of his successors, Andrew Plimer (1763-1837) whose delight ful portraits are often marked by forced chiaroscuro, experiments in strong colour and most inaccurate drawing. Plimer had a brother Nathaniel, who did better work than did his elder brother, and his miniatures are much smaller, and more difficult to acquire.
Perhaps the most popular man of this period was George Engle heart (1750-1829), who was responsible for nearly 4,000 minia tures, a careful account of which he kept in his ledgers. His work is bolder and stronger than that of Cosway. His paintings are usually signed by an initial, and often dated.
The most skilful draughtsman of the period was John Smart (1741-1811) whose work excelled all that of his contemporaries in its silky texture and elaborate finish, and in the extreme skill with the flesh, perchance sometimes too ruddy in colour, is painted. Amongst all the group, Smart alone seems to have had a profound knowledge of anatomy.
One of the most delightful miniature painters of the day was Ozias Humphry, whose work is broader than that of his contem poraries, and who was in many respects an original genius. Towards the end of his life, owing to failing eyesight, he had to devote his time to pastel painting. Nathaniel Hone and his son Horace Hone, Peter Paillou (1740-1800) and William Wood (1768-1809) are painters who stand out in somewhat marked fashion.
, At the end of the i8th century, another group of artists come into view, such as Shelley, whose best portraits are groups of two or three persons, Hargreaves, a Liverpool painter, Mrs. Mee, who was responsible for a large number of portraits, Edridge, who drew also in pencil full length portraits, colouring the faces in miniature fashion, as did Cosway, Nixon, Collins, Crosse and others.
Lawrence and Raeburn, in the early part of their career, both painted miniatures, but works that can be definitely attributed to either of them are extremely rare, and can very seldom be identi fied. Hoppner is said to have painted one or two miniatures, one only is known bearing his signature.
Andrew Robertson started quite a new fashion in miniature portraits, desiring to make them more like small-sized paintings in oil, but his pigments were water-colours used with extreme skill and great knowledge. His paintings are particularly brilliant and also often executed with a very dark background, and full of dignity and force. The desire gradually came about in his time, and the time of those who followed him, to have much larger portraits than had hitherto been called miniatures, and at that period there was introduced the process of flattening out curved slices of ivory by hydraulic pressure. This enabled such men as Sir William Ross, Chalon, Newton and Thorburn to paint portraits of unusually large size, as large, and in some cases, larger than an octavo sheet of paper. In some instances, the ivory, by reason of climatic changes, has returned in a slight degree to its original curved shape, and hence these larger miniatures are often slightly cracked. Of this latest school, Chalon and Newton were the only two who worked in broad masses, the others, notably Ross, had an almost microscopically minute technique, and invariably worked under a magnifying glass.
, All this school devoted too much attention to costume and acces sories, and too little to the representation of the human face, pre senting their works, moreover, in full direct light, with but little shadow, and comparatively formal and stiff in their positions.