Figure 34. Some Roof Treatments, Suggesting Shingles, Slate, Thatch and Tile.
Figure 35. Various Indications of Brickwork and Stonework.
A little observation will answer such questions as these and make it evident that ordinary window glass has two leading characteristics which relate especially to its appearance, and which are, therefore, of the greatest importance to the student. First comes its transparency. Under certain conditions glass seems practically invisible. This is especially true of clean plate glass favorably lighted. We are sometimes able, then, in our representation of windows, to neglect the glazing and treat the sashes just as though the panes were non-existent, showing distinctly the shades and hangings within, or, if the drawing is made from an interior, looking out, the foliage and sky beyond. The other characteristic, and the one which causes much of the trouble of the beginner, is the power that glass has to act as a reflector or mirror, giving, very often, a shiny effect to the window, and usually images of objects as well, which in some cases are almost as clear as those obtained in the usual "looking glass." One of the difficulties confronting the student who tries sketching directly from buildings is the complication in the effect of glass resulting from these reflections, for often trees and buildings and skies and clouds and people are all pictured in the windows, showing so plainly as to prove confusing, for the images are not only somewhat distorted, as a rule, because of imperfections in the glass, but are crisscrossed by the sash bars and mingled and blended with the curtains in a most bewildering manner. It is not easy, therefore, to know just what to put in and what to leave out. so considerable experience will be necessary to teach what really is essential and what should be subordinated or omitted. It is worth remembering that as a rule the two characteristics of glass which we have mentioned appear in combination; - the glass seems sufficiently transparent to enable us to see through it quite easily yet has enough reflection to give it a shiny appearance. Sometimes, however, this power to reflect neutralizes the effect of transparency to such an extent that we find it impossible to look through the panes at all. This is especially true in windows near the top of a building where the reflection of sunlight or bright sky is frequently so strong as to make the curtains within either invisible or very indistinct. Such windows, and particularly those of the upper stories of very tall buildings, often take on much the same color and tone as the sky, and if the sun itself is reflected, the windows become dazzling in their brilliancy. A reflected light cloud may make the glass almost white, while a blue sky may cause a blue reflection of a value similar to that of the sky itself. If we observe the windows nearer the street level we find as a rule that most of them seem darker, for in place of the sky reflections we have those of nearby buildings and trees. It is useful to bear in mind, then, that when rendering tall buildings the general tone of the glass, taken as a whole, may often be correctly shown lighter in the upper than in the lower stories. Even in the ordinary suburban home or country house the windows of the lower floors frequently seem darker when viewed from without than do those above, especially if the nearby foliage is comparatively low, so as to reflect in the downstairs windows only. It is true, too, that glass within shadow, or on the shady side of a building, usually seems much lighter than we would expect, so it is by no means necessary to represent it by a dark tone simply because it is within shade or shadow. Its light appearance is generally due to the fact that it mirrors the brightness of the sky or some nearby building in sunlight. This power which glass has to reflect varies under different circumstances. If glass has black or darkness as a background, or is in shadow as we have just mentioned, it usually proves a stronger reflector than it does when in light or with light shining through from behind, or with a light background. Paint glass black on the back and it becomes a good mirror, reflecting objects very distinctly. When we look at a window from without, in the daytime, and it has no shades or curtains, its glazing may be likened to the painted glass just mentioned, the darkness of the interior being relatively of a deeper value than the outdoor tones and therefore taking the place of the black paint, and such a window shows reflections more distinctly than one with light curtains behind. If a window by chance shows portions of a black, or any very dark window shade and of a light one as well, the reflections will be more distinct on that portion of the glass which has the dark shade behind it, and contrarily if a similar window has a light shade lowered to the sill so as to fill the whole opening the reflections will be comparatively indistinct. As a further proof that glass is a good mirror when backed up with black, stand facing a window in a lighted room at night, with the shade raised, and if it is dark out-of-doors your own image can be easily seen. In the daytime, however, if you stand in the same place and look out into the sunlight you will find your reflection to be quite indistinct or even invisible. When making a drawing of an interior as it appears in the daytime it is, therefore, seldom necessary to show any reflections in the glass of the windows or doors of the outside walls, as the brighter light without renders them impotent. In fact in architectural drawing it is only occasionally that definite reflections of objects are shown, for unless extreme care is used to keep them inconspicuous they may become so noticeable as to seriously detract from the result. It is not often advisable, for instance, to show the reflections of tree trunks or nearby buildings, and if such images are indicated they should be drawn correctly and kept subordinated. There are times, however, when a reflection of a window reveal or an arch intrados or some similar adjacent part of a building may prove interesting, and in the sketch at "5," Figure 36, a dark reflection of the shaded intrados is shown. Even though comparatively little use is made of definite images of objects, when representing glass, the effect of most windows is, nevertheless, modified to such an extent in general tone by the indefinite reflections of the sky and distant objects as to demand some expression of this modification, but as the spectator, when viewing a drawing, seldom has an exact knowledge of what these objects influencing the appearance may be, the artist is usually at liberty to assume such conditions as best suit his requirements and convenience. This means that if it pleases him to draw his windows light, on the assumption that they are reflecting a bright sky, or dark for some similar reason, he is at liberty to do so, and as windows often change in effect completely and suddenly, it is hard to dispute his authority.