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Table of Contents

35. Glare.—Any brightness trying to the eyes—direct sunlight, reflected sunlight that is too bright on window, wall, ceiling or desk. A broad expanse of blue sky. Direct passing through translucent shades, etc.

36. Brightness Contrast.—A patch of sunlight on surface area adjoining a normally-lighted area. A shadow adjoining a normally-lighted area with distinct line of demarkation.

37. Specific Brightness.—A determined condition of brightness. The eye can see better with low specific brightness than with high.

38. Quality of Light.—There is a definite light condition which permits the normal eye to act without strain. To depart from this condition through obtaining more light, less light, or variation in light color, decreases the quality.

39. Reflecting Surfaces.—All surface areas in the room—walls, ceiling, floors, tops of desks, pictures, maps, etc.

40. Specular Reflection.—Image reflection as from a looking-glass. Concentrated reflection which reflects in a concentrated and direct manner. Reflection from bright surfaces which furnish glare or dazzle.

41. Diffused Reflection.—Reflecting in a spread-out manner so that no image appears. Reflecting without glare or dazzle.

With these definitions in mind, the following set rules become intelligible.

Windows should pass a maximum amount of light without the direct rays of the sun or a broad expanse of blue sky appearing. The light so passed should be deflected through the room in a diffused and evenly-distributed manner, so that glare and brightness contrasts do not appear. All reflecting surfaces in the room must cause diffused reflection and not specular reflection, and be finished so that quality in light color is not lowered and a specific brightness occurs which permits the eye to act normally and restfully.

Is this condition possible with suitable window openings and opaque semitranslucent or translucent fabric shade?

With fabric shades, it is impossible to properly regulate or control light. A sufficient and proper light near the window openings means too little light at points further removed. In other words, a proper and even specific brightness throughout the room cannot exist.

Again, by covering the entire window area with opaque or semitranslucent shades in order to cut off the direct rays of the sun, so as to avoid strong brightness contrasts, too little light is admitted. To allow any of the direct rays to enter through covering only part of the window area with the shade, brings about the condition of strong brightness contrasts, which it is always necessary to eliminate. Translucent shades should never be used, as they always create strong brightness contrasts.

With fabric shades, no matter how the window is placed, light can never enter properly. Light should always come from above down upon the work surface, so that lines of demarkation cannot occur, no matter where one may sit. With fabric shades all light must either pass horizontally through the room, or be reflected from the floor up, to be in turn reflected from the ceiling. These conflicting angles of light cause many lines of demarkation, and necessitate a constant refocusing of the eyes, even in the limited space of a book page.

There is only one way to properly daylight a room. There should be at the window a device which will pick up all light that strikes the window opening and deflect it to the ceiling, from where it is reflected so as to fall evenly, perfectly diffused, throughout the room. In this way all light is reclaimed and used and not blocked as with fabric shade. In addition to this, perfect ventilation can be secured, and windows may be opened without fear of direct draught and ensuing colds. Such a device, endorsed by the medical profession, is obtainable, so the impossible is not asked.

If the light is thrown to the ceiling, it is evident that this should be a maximum reflecting surface. A proper maximum reflecting surface can only be obtained through using white which must diffuse and not be specular in character, so as not to dazzle. The ceiling, therefore, should be painted (not kalsomined) a dead flat white. This will furnish a strong white light. Too strong, in fact, unless toned by some neutral light from the side walls. To secure this, all side walls should be painted soft neutral tints, dead flat in finish (this prevents specular glare) which will be pleasing and soothing in appearance. A soft, yellowish green has shown by scientific tests to be the best color.

Special Brackets.—Special brackets are on the market which allow the lighting to be partially controlled. These fit close to window frames, and can be extended as well as adjusted to height by travelling sockets. This shade is of one piece when rolled, and can be left at either top or bottom of the window.

Color of Fabric Shades.—A great deal has been said about the best color for fabric shades, and many experts agree that a light "bisque" makes a very satisfactory color, not light enough to annoy or dark enough to exclude the light. Hollands are to be avoided on account of the reflections cast.