If the surface of vellum is examined very carefully it will be noticed that one side is different from the other. The side which was originally the hair side of the skin is rougher than the flesh side. The smoother side is nicer for writing upon, although, when using one side of the vellum only, it is not advisable for the beginner to use the flesh side, as it is so difficult to make an erasure on this side, without spoiling the skin. Of course, it is much better to endeavour to avoid making mistakes, but still it is almost impossible to prevent them occasionally. When it is necessary to make an erasure a very sharp knife should be employed with the least possible pressure. For erasures on the flesh side of the vellum the kind of rubber known as kneaded rubber is very useful. This erases very slowly, but at the same time very efficiently. When using a knife for erasures on vellum it is essential that it should be extremely sharp and that scarcely any pressure be put on it. It is best, however, to avoid the use of the knife on the flesh side of vellum.
A simple but effective style of illumination is shown in [Fig. 31]. This is based, to a large extent, on pen-work. The block of the initial P may be blue, with the centre red. The initial itself is of raised gold, as also are the buds and centres of the small flowers in the surrounding decoration. The fine scroll-work may be in black or brown, the decoration on the initial being white.
Fig. 31.
After the lettering is completed, the decoration should be drawn in carefully with pencil. The scroll-work may then be drawn in with the pen. The page should then be carefully cleaned with a piece of soft rubber, removing all pencil-marks that will not be covered with colour. The next step is the gilding. Various preparations are sold by different artists’ colourmen for this purpose. When buying gold-size, however, the student should see that he gets the kind specially prepared for illuminating. There are many varieties on the market, some of which are useless on vellum. For example, it would be foolish to try and gild on vellum with oil gold-size or japanners’ gold-size. Also the different kinds of water gold-size, used by decorators and picture-frame gilders, are difficult to use on vellum, as the gold is laid by flooding the surface of the size with water and then applying the leaf. The result of this is to cockle the vellum in a most unpleasant fashion.
Most dealers sell raising preparation and water gold-size. The raising preparation is generally sold in two distinct forms by different makers, one in the form of a thick paint and the other a thick jelly, which requires heating to liquefy ready for use. The former kind will be found the most satisfactory.
A small ichneumon brush may be used for applying the raising preparation. Before filling in the parts that it is desired to raise it is not a bad plan to roughen the surface of the vellum slightly in these parts. This will help to prevent the raising from scaling off when it dries.
Difficulty is often experienced through air-bubbles in the raising preparation. In drying, of course, these show as tiny holes. In this case prevention is better than cure. These bubbles are generally introduced into the preparation by means of the brush. The brush being full of air is used to stir the preparation, and the air leaves the brush in the form of bubbles, which mix with the raising preparation. The best way to use the raising preparation is to take a small quantity out of the bottle and place it in a small saucer. It should then be carefully worked up with the finger-tip with a little water until it is about the consistency of cream. It is much better to use the finger-tip to mix it up with rather than a brush. Using a brush for this purpose is a fruitful source of air-bubbles, besides spoiling the brush. Before using the brush to lay on the preparation with it should be shaken vigorously in water and squeezed out, thus displacing the air and preventing the formation of bubbles. All the parts that it is desired to gild should be given a fairly substantial coating. It should be almost dropped from the brush. It is not desirable to raise it too high, or the effect will be somewhat tawdry. The student should use the work of the mediæval artist as his guide in this direction. When this is all filled in, the work is placed in a room free from dust for the raising to dry firm and hard. The surface is then scraped carefully with a knife until it is quite smooth, all little irregularities being removed.
It is then given a coat of water gold-size, and when this appears dry on the surface it is breathed upon until it becomes tacky. The leaf is then cut to size and laid on at once, pressed down with cotton-wool and left to dry. The superfluous gold is then brushed away with a camel-hair mop. On the following day it may be burnished. If the burnisher does not work freely on the surface, its action may be facilitated by rubbing the surface of the gold with a soft cloth that has been slightly smeared with beeswax.
When using the water gold-size it is most important that this should be kept free from dust, and especially small hairs and pieces of fluff that often float about in the air. It is impossible to gild successfully if the size is full of these. After painting on the size it should not be allowed to get thoroughly dry before laying the leaf—it should only appear dry on the surface. If it is allowed to get properly dry it will be next to impossible to make it tacky by breathing upon it.