When you are working from still life or from a model this is often an advantage, for you can have a strong side-light on the model, and a second light on the canvas. To arrange this, have a sort of crane made of iron, shaped like a carpenter's square, which will swing at right angles with the wall, the arm reaching, say, six feet into the room. Swing this by means of staples well up to the ceiling, so that the light cannot get over it, and near to the right-hand window. From this arm you can hang a thick, dark curtain, which will cover and shut out the light from the right-hand window when swung back over it. If you want to pose your model in the light of that window, while you paint in that of the other, swing the curtain out into the room at right angles to the wall, and it will prevent a cross light from the two windows; so that when the model is posed back of the curtain the light from that window will not fall on the canvas, nor the light from the other fall on the model.
The light will be best on your picture coming from well above you as you work. There will then be no reflections on the paint. You may find it necessary to cover entirely the lower half of the window which gives your painting-light. You will find it useful to have a shade of good solid holland, arranged with the roller at the bottom, and a string running up through a pulley at the top; so that you may pull the shade up from the bottom instead of down from the top, and so cut off as much of the lower part of the window as is necessary.
If you need the light from the lower part of the window, you may make a thin curtain of muslin to cover the lower sash, which will let the light through, but diffuse the rays and prevent reflection.
The Size of the Studio.—Of course a large studio is a good thing, but it is not always at one's command. But you should try to have the room large enough to let you work freely, and have distance enough from the model. The size that I have mentioned, twelve feet by sixteen, is as small as one should have, and one that you can almost always get. If the room is smaller than that, you cannot do much in it, and fifteen by twenty will give ample space.