The pose of the body and hands can be a great aid in obtaining a likeness but if too much emphasis is laid on action the attention can be diverted from the head. For the ancient Greeks the body had as much significance as the head ; now after ages of neglect, it is coming to its own again, and the modern artist should make the most of this opportunity. The choice of costume is of the greatest importance. As every woman knows, different dresses bring out different qualities in their face. Often when an artist is unable to obtain the desired expression he finds that changing the dress is all that is necessary. The lines of the costume react on the lines of the face just as in music a note has its overtones. This is why artists are always glad to use scarfs, furs or anything they can arrange themselves.
One of the most difficult problems is that of the background, which is just as important as any other part of the portrait. It can be compared to the accompaniment in music, strengthening by relative values the illusion of colour and form in the figure.
Each portrait presents its own individual problem. The surest way to fail is to try to develop a formula. It is impossible to paint two subjects with the same methods. For this reason great artists often have stage-fright before beginning a portrait. The brush work which makes the work of Rembrandt, Hals and Velasquez so astonishing was certainly not planned in advance but dictated by the inspiration of the moment and the vividness of the impression made on the artist. This does not mean that the artist should make experiments on his clients. He should not accept a commission to paint a portrait before he has solved all technical problems on portraits of friends or of hired models. It is one thing to paint from a hired model, accustomed to sit for many hours and indifferent about the results, and another to deal with a client easily fatigued, pressed for time and entitled to have a word in the proceedings.
A portrait painter can rarely put his canvas aside, forget about it and take it up again after months, when his vision is fresh. For this reason he must depend on comments made by the client and his friends, trying to glean from them where the trouble lies. It is rarely where the layman thinks but with experience and a little psychology the artist can profit by learning how the portrait reacts on different people. However, remarks offered before he is ready for them can be very harmful. It is difficult for the layman to realize that a portrait cannot be a perfect likeness until it is entirely finished ; nor that the artist must work up all parts of the picture simultaneously in order to make a harmonious whole.
He cannot finish the head and then progress to the body and hands any more than an architect can finish one room in a building before the roof is on. Each colour, each line, in a picture affects all others. It is their relative value alone which gives the illusion of form.
Modern artists as a rule paint directly, trying to place the right tone in its right place immediately. Charles Hopkinson recom mends the process probably used by many of the old masters. Over a monochrome under-painting he models carefully with red, black, white and blue, mixing the lights with red and white; the shadows with red and black. These simple tones permit him to devote his full attention to the form. When this under-painting has dried he glazes with the bright colours, the yellows, bright reds, greens, etc. Rich, luminous transparent tones are obtained in this manner and by contrasting transparent flesh tones with opaque touches in accessories a great variety of texture is obtained. Both processes have their advantages and their disadvantages. Glazes do not permit a very sincere study of colours in relation to other colours and they can endanger the durability of the painting. Many of Reynolds' canvases faded, cracked and pealed off during his life-time. The direct method is very durable if it is not retouched too soon, but many of Sargent's portraits covered with cracks are sad examples of what happens when paintings are worked upon before they are thoroughly dry. Titian and Rembrandt are said to have let their work dry for months, but few modern people would be able to let their sittings cover so long a period.
The frame should be chosen before the portrait is finished and the final work on the canvas should be done after it is framed. The frame can be toned and antiqued so that the whole is har monious. An unsuitable frame can affect the likeness and cause great trouble to the artist. It is well for the artist to know be forehand where the portrait is to be hung. He can then arrange his colouring and lighting to harmonize with the surroundings. Some people decorate their rooms to bring out a picture. The illusion of form is more vivid if the portrait is hung with the light falling from the direction of the light in the picture. The client should live with the portrait for some time before request ing changes. Often he becomes reconciled to the artist's vision and does not wish changes made which generally impair the beauty of the whole for the sake of some detail.