IT is necessary to remember, in preparing a sketch or picture for reproduction by the halftone process, that, as in the case with any other reproduction by photography, while some colours photograph well, others are totally unsuitable for photography. A brown is highly satis-factory for photography, while a cold bluish tint is not good, and work done with it is apt to come out several tones lighter than the original.

The wash drawing in water-colour yields excellent results. The surface is perfectly dead, and all the lights and whites are represented by the white paper. Oil is not a good medium, owing to the gloss on the surface of the painting; besides, even when clone in ivory or lampblack, the painting is almost bound to have more or less of a bluish tint. Remember that when mixing white with the black, the latter is apt to turn blue, whether you are working in gouache or in oil-colour. To rectify this, add plenty of brown. Even let your drawing be brown - and a warm brown, too. Biastre answers admirably.

If blue be used in mechanical reproduction, the result is sure to be poor. Perhaps the very best medium of any is Winsor & Newton's "charcoal wash." It is perfectly black in the dark, and in the light washes inclines to brown; the lights here are the plain white paper, no body colour being used.