If a little colour is left in the saucer after using it, it can easily be moistened up again with a little water. It is not, however, advisable to mix up much more than is required, as it dries rather hard and requires soaking some little time if a considerable quantity is left to dry.
When mixing colours in this way it is as well to label carefully the bottles in which the colour is stored. If this is not done, one is very liable to mistake a fugitive colour for a permanent one, and vice versâ. Cadmium yellow may easily be mistaken for chrome yellow, and crimson Lake for permanent crimson.
CHAPTER XVI
THE GILDING METHODS OF THE MIDDLE AGES
The most casual observer cannot fail to notice the gilding that is such a prominent feature of the MSS. of the mediæval period. Brightly burnished gold, which appears as if it had been laid and burnished quite recently, although centuries have passed since the work was completed, cannot fail to impress and arouse one’s curiosity as to the gilding methods employed when this work was produced.
Some of the old MSS. that treat of painting and the preparation of colours give also some information concerning the various methods of gilding, and our knowledge of these methods is chiefly derived from these MSS.
Dr. A. P. Laurie has made careful examination of the different forms of gilding employed in illuminated MSS., and in his book, “Pigments and Mediums of the Old Masters” says that gold was used in three distinct forms: as gold-leaf laid on the surface, and in the form of gold paint, prepared by grinding leaf-gold to powder; the other method seems to have been a paint made of rounded granules of gold. He suggests that this gold was probably obtained from river washings, and that the only preparation has been to sift out the finer grains. He says, further, that when it is examined under the microscope this form of gold paint is easily distinguished from that prepared from leaf-gold, which presents the appearance of little particles of gold with sharp corners and edges, while this shows rounded granules.
The art of gold-beating is of very great antiquity. Pliny, in his “Natural History,” states that one ounce of gold was made into 750 leaves, each leaf being four fingers square. This is about three times as thick as the ordinary gold-leaf of the present day. It is very difficult to form any idea as to when and where it originated. Some think that it arose amongst Oriental peoples. It certainly has been practised amongst these since quite remote periods. Some of the coffins of the Egyptian mummies have gilding on them evidently done with gold-leaf in a similar way to modern methods. Some of the books of gold-leaf used by the ancient Egyptians are in existence to-day, there being one at the Louvre in Paris.
Pliny says, “Gold-leaf is laid over marble, etc., with white of egg, on wood with glue properly composed; they call it leucophoron.” In another place he states that leucophoron is composed of sinopia (a red earth colour), light sil (yellow ochre), and melinum (a white earth). Evidently this was mixed with size to form a ground upon which to lay the leaf.