If a painting has been repainted only in the parts that were missing, and the old varnish has not been removed from the rest of the picture, it is a question of not only giving the varnish of the new spots cracks like the old varnish, but these must imitate as closely as possible those of the original part of the painting. In such cases a needle is used to make the cracks on the newly varnished parts. When the grooves have been made in the varnish they are filled in with water and colour or soot to give them the desired appearance of age. Such, roughly, is the method mostly in use for oil paintings. With the necessary variations, and the use of the proper medium, the same method also answers for tempera. It is rare that frescoes are imitated or retouched, but in such cases fresh cheese is used as the vehicle for the colour, and when dry it not only acquires the quality of insolubility but also the opaque hue of the fresco. As far as technique is concerned, the imitator does not find it easy to imitate the work of those artists who paint in impasto, that is to say with a thick layer of pigment, the consequent characteristic strokes of the brush requiring no little experience for reproduction in all their force, character and characteristics. Through long study and practice some finally succeed in imitating the work of such painters as Rembrandt or Frans Hals, but such cases are extremely rare. Forni, who has written a work on the restoration of paintings, suggests a method of imitating impasto painting with its characteristic brush strokes which, in our view, can only be applied in the case of repairing a part missing in some old painting. Forni’s method consists of first reproducing the peculiarities of the brush strokes in a plaster composition closely resembling that of the preparation of the canvas, and then giving the proper colouring. According to Forni this method has the advantage of giving the impression of a frank and vigorous style of painting such as is usual with the impasto technique, and yet it has been achieved slowly and patiently. One of the side-businesses of picture faking is the providing of suitable signatures. When one considers that paintings generally bear the artist’s signature, more especially in recent times, it would be strange if this branch of the shady trade did not number specialists who can imitate signatures to perfection, as well as reproduce artists’ special monograms.