Light and Shade

A Classic Approach to Three-Dimensional Drawing

Mrs. Mary P. Merrifield

• Editore: Dover Publications
• Anno: 2012
• ISBN:
  9780486139883
• Argomento: Kunst
• Categoria: Kunsttechniken

“Form,” writes the author, “is developed by means of light and shade; without these every object would appear flat.” Originally published in the mid-nineteenth century, this classic approach to three-dimensional drawing was the first book to provide art students with instructions for correctly illustrating perspective outlines of various objects.
An art historian noted for her authoritative reference works, Merrifield clearly demonstrates the principles of light and shade by revealing the effects of common daylight, sunshine, and candle or artificial light on geometrical solids. Her simple explanations are accompanied by illustrations of cubes, prisms, pyramids, cylinders, spheres, ovals, and cones.
As useful and practical today as it was when first published well over a century ago, Light and Shade provides beginning and advanced art students with valuable insights into effective drawing and sketching.

HANDBOOK

OF

LIGHT AND SHADE.

LESSON I.

GENERAL PRINCIPLES.

FORM is developed by means of light and shade; without these every object would appear flat.

All colour is a deprivation of light; therefore, if several objects of the same shape, some of which are coloured and some white, are situated similarly with regard to the light, the white objects will be lighter than the coloured ones.

Every solid opaque body has one part on which the light is brightest, and one part on which the shade is strongest, the other parts being of an intermediate tint.

The intermediate tint is called the middle tint, because it is equally removed from the extreme light and the extreme dark.

The intermediate tint may be subdivided into the half light, the middle tint, and the half dark. (Fig. 1, P1.1.)

The middle tints occupy the largest portion of the object, the extreme light and dark being limited to a very small space.

The brightest part of an object will be that on which the light falls directly.

The brightest part is called the high light.

The shadow side of an object will be that which is opposite to the light.

The shadow side is not synonymous with the shadow.

The extreme dark of a rectilinear object will be found generally close to the extreme or high light.

The shadow thrown by a white object is darker than the darkest side of that object.

In an opaque solid bounded by circular lines the extreme light will be found a little distance from the edge on the light side, and the extreme dark a, little distance from the edge on the dark or shadow side, while on the intermediate part, the shade will melt gradually into the light.

LESSON II.

OF THE LIGHT UNDER WHICH OBJECTS ARE VIEWED, AND OF THEIR SHADOWS.

Objects are viewed under three kinds of light, namely, sunlight, ordinary daylight, and artificial light; and the effect varies according as they are seen under one or other of these lights.

As a general rule, the brighter the light the stronger and more distinct is the shade; in ordinary daylight the shadows are less distinct, and in dull weather they are scarcely visible.

When lighted by a single light, opaque objects can 11 be illuminated on one part only, the space situated on the side not lighted is said to be in shadow; the space on the ground, or on another object from which the light is obscured by an opaque solid, is called the shadow.

Shadows are analogous in form to the body by which they are cast; thus the shadow of a perpendicular is a straight line, the shadow of a rectilinear figure is rectilinear, that of a sphere is circular.

The shape of shadows is discernible only on their outlines, and is modified by the form of the surface on which they are thrown.

In sunlight the source of illumination (the sun) is at so great a distance, and of such magnitude in comparison with the objects lighted by it, that the luminous rays which fall on our globe are supposed to be parallel, and as such they are always to be treated in daylight scenes. The higher the source of light, the shorter will be the shadows; thus, at morning and evening, when the sun is low, the shadows are long, while as the sun rises the shadows become shorter, and are shortest at noon. In summer, when the sun attains greater altitude, the shadows at noon are not so long as at the same hour in winter, when the rays strike more obliquely and the sun is nearer to the horizon. There are certain places within the tropics at which the sun is sometimes vertical, so that if at noon a stick be set upright in the ground it will cast no shadow.

Where several straight lines are parallel to each other the shadows thrown by these lines upon a horizontal plane will also be parallel to each other, and the perspective representations of these shadows will converge towards the same accidental points as the perspective representations of the lines themselves. (See Lesson XV.)

If the shadow thrown by a solid object is intercepted by other objects, such as a fallen tree or pillar, a wall, or a house, it is carried along the surface of these objects, and is terminated by the ray which, proceeding from the seat of light, touches in its passage to the ground the upper edge of the body which throws the shadow. In Fig. 2, P1. 1, the shadow of the cylinder or tower is cast first upon the ground, then, ascending the wall of the house, it crosses the roof, where it terminates. The oblique line, A B, shows the direction of the ray of light.

The perspective of shadows will be treated in a subsequent lesson.

From artificial light the rays diverge equally all round.

If more than one artificial light be present, objects will have as many shadows as there are lights; and, as these shadows frequently intersect each other, it becomes very difficult to distinguish their true shape, and, consequently, to represent them. The same thing takes place, but in a lesser degree, in the day-time, when the light is admitted by more than one window; in the latter case, however, the light being more equally diffused, the effects of the cross-lights are not so palpable to the casual observer. Objects seen under these circumstances also want that lucid and intelligent arrangement of light and shade, and breadth of effect, which are essential to pictorial representations. It will be understood, then, that when objects are to be represented in light and shade, they must be illumined by one light only.

We have now to speak of the situation of the light. When the sun is the illuminating body, it is always above our heads, and the shadows are in consequence thrown downwards. This, which is the natural, is also the most agreeable disposition of the light, as well as the most convenient. It is imitated by painters, who close up the lower windows of their studios, admitting the light only from above.

In an out-door effect the sky will be the brightest part, in an in-door effect the brightest light will fall on the floor.

Independently of its height, the situation of the sun with regard to the spectator is continually changing. It may be on the right hand or the left, before or behind him. If it be behind him, the illuminated side of objects will be presented to him, and will want shadow. If it be before him, the shadow side of the objects will be next to him, and the picture w...