Terra di Siena, a yellow hard and clayish substance, so called from the city of Siena in Italy, from whence it comes.
This colour is very unfit to be used crude, either for painting in encaustic or crayons, its pores are too close for the wax to penetrate; or to say better, this colour or earth is very much impregnated with a nitrous principle, with which wax cannot sympathise, and for this very reason it is as unfit to be used crude in oil. Those painters that use it freely have always but too much reason to repent. But,
Terra di Siena calcined, is a very beautiful and useful colour for all manner of painting, and particularly encaustic. The fire having dispelled in some measure the nitrous principle, the wax may freely enter its pores. This colour gives a great, soft, and glowing strength in flesh, drapery and landscape; some painters call this colour Roman oker.
Terra verte; this colour too comes to us from Italy, and some from Germany, they are both alike, and ought to be entirely banished the pallette, as it grows so soon dirty and black when employed with oil. Terra verte differs from terra di Siena in little else but colour, it has a little vitriol. The too free use some of the older Italian painters made of this colour in flesh tints, is the cause that numbers of pictures of those masters are so black as we see them at this time.
BLUES.
- Ultramarine,
- Prussian blue,
- Smalt.
Ultramarine is perfectly good, and every body that likes to use it may do so.
Prussian blue, equals ultramarine in encaustic, for all intents and purposes; there is no other blue required for crayons neither.
Smalt may be used, but I think it rather too gritty; its particles are too transparent for parts where a solid mass of colour is required. For crayons it does very well mixed with Prussian blue to bind it, both together make a beautiful colour, the grittiness of smalt will there be of advantage. This colour will not grow black fixed with wax as it does in oil.