Valuable Secrets concerning Arts and Trades:
or Approved Directions, from the best Artists, for the Various Methods...
Printed by Thomas Hubbard,
Norwich, 1795Chap. V. Secrets concerning colours & painting.
§ VIII. Preparations of colours of all sorts for oil, water, and crayons.
CXIV. Directions for painting fresco.
Begin first, by laying on the intended wall a coat of sifted river sand, mixed with old slacked lime, pulverised and sifted also. - This coat is not to be laid on the wall, but in proportion as you paint; therefore, you are to prepare no more at a time than you are sure to paint over in one day, while fresh and moist. - The body of the wall on which you lay this coat must previously be pargetted with plaister, or with a mortar made with sand and lime. And if the paintings are to be exposed to the injuries of the weather, the mason's work must be made of bricks or free stones very dry.
2. Before you begin to paint, you must prepare your designs in their full intended size on paper, and chalk them one after another, as you go on, on the wall, in proportion as you work, and no longer than half an hour after the coat of prepared river sand above mentioned has been laid on, and well polished with the trowel.
3. In these sorts of paintings all the compounded and artificial-made colours, as well as most of the mineral ones, are rejected. They use hardly any other but earths, which may preserve their hue, and defend it from being burnt by the lime. And, that the work may for ever preserve its beauty, you must observe to employ them quickly, while the coat underneath is still moist; and never, as some do, touch them over after they are once dry, with colours diluted in yolks of eggs, glue, or gum, because these colours always blacken, and never keep that vivacity and brilliancy those have which have been laid at first when the ground was moist. Besides, in the case of paintings exposed in the air, this sort of touching up is never good for any thing; and, too often, scales off in a very short time.
CXV. Directions for the choice, use, and composition, of the colours employed for the above purpose.
The colours made use of, for the above purpose, are such as follow.
1. The white. This is made with a lime which, has been slacked for a great while, and white marble in subtile powder, mixed in about equal quantities. Sometimes no more than a quarter part of marble dust is required; which depends entirely on the quality of the lime, and cannot be known but when you come to use it; for if there be too much marble, the white will turn black.
2. Ocher, or brown red, is a natural earth.
3. Yellow ocher is also a natural earth, which be comes red if you burn it.
4. The obscure yellow, or yellow ocher, which is also a natural earth, and slimy, is to be got by the streams of iron-mines. It receives a fine colour from calcination.
5. Naples yellow, is a sort of filth which gathers round the mines of brimstone; and, though it be used in fresco-paintings, its colour nevertheless, is not so good as that which is made of earth, or, yellow ocher and white mixed together.
6. The purple-red is a natural earth, the product; of England; and it is used instead of lake.
7. The terverte, from Verona in Lombardy, is a natural earth, which is very hard and dark. There is also another sort of terverte.
8. The ultramarine, or, lapis lazuli, is a hard stone, and of a very difficult preparation. This colour, of the manner of preparing which we shall give (§ ix. Art. cxxxiii.) a just and precise account, subsists and keeps itself fine much longer than any other colour. It is not to be grinded, but diluted only on the pallet with oil. As it is very dear, you may spare using it in fresco paintings, and supply it by smalt, which answers the same purpose, particularly in skies.
9. Smalt is a blue colour, which has very little substance. It is used in great landscapes, and stands very well the open air.
10. Umber is an obscure earth. It requires to be calcined in an iron box, if you want to make it finer, browner, and of a better look.
11. Cologn earth is a sort of rusty black, which is apt to discharge, and to turn red.
12. The earthen black, is a black which comes from Germany. - There is also another sort of German black, which is a natural earth, and makes a bluish black, like that of charcoal. This sort of black is that which is used for making printers' ink. - There is another still, which is made with burnt wine-lye.
Such are all the colours which are preferably to be used fresco-painting. Grind and dilute them with water. - Before beginning to work, prepare your principal colours, and put each by themselves, in small gallipots. But it is necessary to know, that except the; purple-red, the brown-red, the yellow ocher, and all the blacks, (those particularly which have pasted thro' the fire) turn paler as the fresco dries.
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