This section is from the book "Cyclopedia Of Architecture, Carpentry, And Building", by James C. et al. Also available from Amazon: Cyclopedia Of Architecture, Carpentry And Building.
It is always a very important matter to decide what direction shade lines shall take. "While it is impossible to give rules for it, a good general principle is to make the direction of the lines follow the contours of the form. The easiest and simplest method is to make all the lines upright. This method is a very popular one with architects. The objections to it are monotony and a lack of expression, but it is certainly a very safe method and far preferable to one where desire for variety has been carried too far and lines lead the eye in a great number of different directions which contradict the general lines of the surface or form. A natural treatment is to adapt the direction of lines to the character of the surface represented; that is, to treat curved surfaces with curving lines and flat planes with straight lines, and in general, lines may very well follow either the contours or the surfaces of the form. In that way variety is obtained and the direction of the shading helps to express the character of the thing represented. This principle must, however, be modified when it leads to the introduction of violently opposing sets of lines. Abrupt transitions must be avoided and the change from one direction to another must be accomplished gradually.
Where a large surface is to receive a tone, the tone can best be made by a series of rather short lines side by side with succeeding series juxtaposed. The lengths of the lines in each of the series must vary considerably in order that the breaks in the lines may not occur in even rows, producing lines of white through the tone. (See Fig. 25.)
The crossing of one system of parallel lines by another system is called cross hatching. This method probably originated in copperplate engraving, to which it is very well adapted, especially as a means of modifying and deepening tones. It also changes and breaks up the rather stringy texture produced by a succession of long parallel lines. It has now become somewhat obsolete as a general method for pen or pencil drawing, largely because the result looks labored, for it is always desirable to produce effects more simply and directly, that is, with one set of lines instead of two or more. If the tone made by one set of lines needs darkening, it is now more usual to go over the first tone with another set of lines in the same direction.
Fig. 25. Method of Breaking Lines Covering a Large Surface.
A great many drawings have been made with shade lines all in a diagonal direction, but this is open to serious objection and should be avoided. A diagonal line is always opposed to the principle of gravitation, and tends to render objects unstable and give them the appearance of tilting. It is often desirable to begin a tone with diagonal lines which, however, should gradually be made to swing into either an upright or horizontal direction.
Materials Required. One Wollff's solid ink black pencil; one F pencil; one HB pencil; two dozen sheets of paper (same as practice paper of other courses, but to be used for examination sheets in this); one red soft rubber; one medium rubber-green or red, with wedge ends; one drawing board; six thumb tacks; one box natural drawing models; one Cross slate; one Cross pencil; one-half dozen sheets of tracing paper.
The principal dimensions in inches are indicated on the model plate. All dimensions and proportions should however be determined by the eye alone. Measurements may be used as a test after the squares are laid in. The figures on the left should be executed first, in order to avoid rubbing by the hand and sleeve.
Figs. 1, 2, 3, 4, 5 are motives from Egyptian painted decoration. Figs. 1, 2, 4 and 5 are all derived from or suggested by patterns produced by plaiting or wearing. The borders of Fig. 3 are derived from bundles of reeds bound together.
As all the figures are large and simple, they should be executed with a rather wide line drawn with the F pencil. Draw the construction lines on this and on all other plates where they are necessary, so lightly that they can be perfectly erased without leaving any indentation in the paper. After the construction lines are drawn out in Figs. 4 and 5, strengthen the lines of the pattern. In erasing, much of the pattern will be removed. This time go over each line with a single stroke of the solid ink pencil. Do not turn the paper in drawing diagonal and vertical lines. They are given especially to train the hand to execute such lines. By turning the paper the exercise becomes one of drawing horizontal lines, which are the least difficult.
PLATE I. Motives of Common Types of Ornament.
Fig. 1 is the basis of a large class of ornament founded on the lines of organic growth, called scrolls or meanders.
Fig. 2 is an Egyptian border consisting of alternate flower and bud forms of the lotus, the most typical and universal of all the Egyptian decorative units. The outline of the flower displays the Egyptian feeling for subtlety and refinement of curve. Observe how the short rounded curve of the base passes into a long subtle curve which becomes almost straight and terminates in a short full turn at the end.
Fig. 3 is a simple form of the guilloche (pronounced geeyosh), a motive which first becomes common in Assyrian decoration and is afterward incorporated into all the succeeding styles.
Fig. 4 is the skeleton of a border motive where the units are disposed on either side of the long axis of the border.