More Points on Perspective

Four Important Points in Perspective – First, the point of sight; second, the horizon line; third, the vanishing point; fourth, the point of station.

The Point of Sight is that spot which the spectator sees when he looks straight before him.

The Horizon Line is a line parallel with the top and bottom of the picture drawn through the point of sight. The distance between the top and bottom of the picture, at which the horizon line is drawn is determined by the point of sight. If the point of sight is high, the horizon line will be correspondingly high. All actual horizontal lines (not parallel from right to left) above the horizon line are inclined toward it. Every receding line of the same kind that is below will run up to the horizon line. The vanishing points, with few exceptions, lie on the horizon line and are independent of the point of sight.

The Point of Sight Becomes a Vanishing Point for all lines (to the right and left of the spectator) that are at right angles to the upper and lower borders of the parallelogram containing the picture.

A large box, open at one end, has its front and back lines in parallel perspective if the opening is parallel with the body of the draftsman as he faces it, while the lines of the sides, top and bottom, recede directly from him. In this case, the point of sight becomes the vanishing point, because all the straight lines receding from the sight converge on this point.

On the contrary, the nearest and furthest lines of the top and bottom of the box being, both in reality and in the drawing, parallel, must be so drawn. These lines, however far they may be extended, would never meet. Whereas, all lines that recede from the spectator would meet if continued sufficiently. (See Figs. 16 and 17. Also see Fig. 4, chapter on Foreshortening. )

The box should now be turned around so one edge is toward the draftsman; thus two sides will be seen, each of which will require its own vanishing point.

In a Picture, There Is But One Point of Sight – There can be several vanishing points. A picture should never contain more than that which can be seen without moving the head. This area is comprised generally within an angle of sixty degrees, or one-sixth of everything the artist could see if he turned completely around as he would in order to sketch a panoramic view, which, however, does not come within the scope of these lessons.

Each Vanishing Point Determined by Point of Station – The point of station is somewhere in front of the landscape or picture, and is, in fact, the eye of the spectator. The distance of the spectator should be at a distance less than the front dimensions of the scene to be enclosed in the picture. That is to say, if the front line of the scene to appear in the picture was one hundred feet wide, the artist should not be stationed more than one hundred feet from the nearest object that appears in the picture. He may, and in most instances should, however, be stationed much nearer.

Locating the Point of Station – The point of station may be determined by having located both of the vanishing points. Or one vanishing point may be determined, which, together with the point of station, will determine the other vanishing point.

Two lines drawn from each of the vanishing points to the point of station should invariably form a right angle.

In the study of perspective it will be helpful to keep the following definitions and rules in mind. Even those already versed in art, through disuse, are prone to forget some of the simplest definitions.