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The Method of drawing Landscapes, &c. by help of a Camera Obscura
Published in "The Oxford Magazine: or Universal Museum", Vol.2, May, 1769, p.169-170
[Typographical changes have been made to improve readability.]
The Method of drawing Landscapes, &c. by help of a Camera Obscura. Illustrated with a Copper-plate.
The method of drawing in a camera obscura, is at once so easy and pleasing, that we were persuaded a few plain directions would not be disagreeable to our readers.
A camera obscura, or dark chamber, is a contrivance for exhibiting the picture of a landscape, &c. in its natural colours, by means of a scioptric ball, through which the rays of light are received on a sheet of paper, vellum, &c. placed in a dark room, or other place, where no light is admitted but what comes in thro' the glass: by which means an exact and similar image of any object before the glass will be formed on the paper; and consequently the whole image, at least the out-lines of it, may be traced with great exactness on the paper, and afterwards coloured if required.
But it must be remembered, that the size or magnitude of the image, painted on the paper, will be proportionable to its distance from the glass; consequently the larger the focal distance of the glass is, the larger will be the picture of the object; and the smaller the compass of the plane or perspective view.
It is also necessary to remark, that the picture of the objects painted on the paper, will be in an inverted position. Nor is this owing to any defect in the glass, but from the rays crossing each other in the center of the glass, in their passage into the camera. For the same appearance would be formed if the glass were removed, and the rays suffered to pass thro' a small hole into the camera; those which flow from the top of the object going to the lower part of the image, and those that come from the bottom of the object to the upper part of the image. The glass has no 'other use than that of rendering the image distinct, by conveying the rays of every pencil to their proper focus in the picture, the position of each point being the same as before.
In the images of landscapes, painted by nature in the camera, the several parts of the picture are either in motion or at rest, according as the objects are in either state. The reason of this is very obvious; and this gives life and spirit to the painting, and is the only particular inimitable by art. But this beautiful addition renders the drawing of landscapes in a camera much more difficult; and therefore calm weather should be chosen for this purpose, when the trees, &c. are not waved by the wind.
Every object is represented in the camera in its proper colours; and because the natural colours of the object are crouded into a less space in the camera, therefore the tints in the painting will be more intense than those in the object; and consequently the landscape painted in the camera, is an improvement even of that in nature itself.
The intensity of light and shadow, or what the Italians call the chiaro oscuro, is also heightened in the picture, as well as the colouring. Here every light, and every shade, is expressed in its proper degree, from the most brilliant in the one, to the most jetty black of the other; together with all the wonderful variety in the several parts, arising from the different situations of the different parts of the object. And it should be remembered, that a just imitation of nature in the distribution of light and shade, is, of all others, the most difficult part of painting, and on which it in a great measure depends for perfection.
Whenever an attempt is made to use a camera obscura, care must be taken to place the lens directly against the object whose picture is intended to be painted in the camera; for if the glass have any other position to the object, the image will be very imperfect, indistinct, and confused.
It will be in vain to attempt the exhibition of the picture of objects in a camera, unless the objects are strongly illuminated; mere day-light is not sufficient, if the beauty of the painting be the principal object; but for tracing the out-lines only, less light will be sufficient.
The best time therefore for viewing the picture of a landscape in the camera, is about noon, when the sky is entirely free from clouds, and the sun-beams strongest. The camera therefore should be placed, as it were, between the sun and the object, that the glass may point directly towards that quarter upon which the sun shines, that the rays flowing from the illuminated parts of objects may present themselves to the lens, and be painted on the paper in the camera, in the greatest perfection. By this position of the camera, none of the direct rays of the sun will enter the camera; a caution very necessary to be observed; because if they are suffered to enter, they will, by mixing with the rays reflected from the objects, greatly disturb the picture, and render it confused.
Explanation of the Plate.
Fig. 1. is a portable camera obscura, made in the form of a sedan chair, and having a door behind; which, in the figure, is represented open. A, a small turret, in which a mirror is placed. B, the mirror, either of glass or metal. C, the tube in which the lens is fastened. D, the table, on which the designer lays his paper, to receive the images of the objects reflected by the mirror B, through the lens and tube C. E, the designer's seat. F, F, ledges of wood for strengthening and darkening the machine. G, G, G, other ledges fastened to the door, in order more effectually to exclude the light, when the door is shut.
Fig. 2. Is another camera obscura, more portable than the former machine just described, and made in the form of a tent. It is placed upon a table, which is no part of the machine. It has the same apparatus on the top, and its uses are the same as those of the former.
The reason for placing a mirror on the top of portable cameras, is to reflect the objects in the landscape thro' the lens and tube, in a perpendicular direction on the paper. And in order to this the mirror operates upon an axis, that it may be set to any angle the operator pleases.