Of all the component elements that together form a completed interior, the single most important element is space. Spaces can be exhilarating or depressing, cheerful or serene, all depending upon the use the designer has made of the various elements that form the whole. Space is, in modern times, a costly commodity. The beautiful space of the Gothic cathedral achieved its success through generous proportions and lofty heights. Due to the vast increase in construction costs in contemporary structures, spaces tend to be smaller and less generous; more skill on the part of the designer is required to give such limited spaces a particular atmosphere or character. On the other hand, sheer volume of space is not sufficient. There is hardly a larger space than the interior of the Vehicle Assembly Building at the John F. Kennedy Space Center in Florida, yet the aesthetic impact of that immense interior is negligible. A space need not be large and monumental to be aesthetically successful. The handling of mass and form even within a small structure can become exciting and beautiful. Frank Lloyd Wright was masterful in creating beautiful spatial sequences within residential-scale buildings. The Ford Foundation building is a relatively small structure among the huge buildings of New York City, yet the experience of that space is real and pleasurable.

Space can be thought of as the raw material which must be molded and shaped with the designers’ tools of colour, texture, light, and scale. The interrelationship of design elements can be clarified by visualizing the result if the interior of St. Peter’s in Rome were painted in garish colours or painted all black or sprayed with a foamy texture covering all surfaces or flooded with enormously intense floodlight that eliminated all play of dark and light. Obviously, any of these modifications would totally destroy the beauty and success of that space.

Colour is the quality of light reflected from an object to the human eye. When light falls upon an object, some of it is absorbed, and that which is not absorbed is reflected, and the apparent colour of an object depends upon the wavelength of the light that it reflects. The scientific attributes of colour and light in interior design are, however, less important than the skillful combination of colour values, hues, tones, shades, and above all textures. Although there can be no strict rules about colours and textures, it is well to remember the famous statement of the modern architect Mies van der Rohe that “less is more.” His Crown Hall at Illinois Institute of Technology in Chicago, built in 1956, is elegant, understated, subtle, and is notable for its careful handling of textures and materials. To accept “less is more” as the sole guideline to design, however, would be a serious fallacy. Space, which is the essence of a meaningful interior, would be dull indeed if it were never varied—if there were no intimate spaces with low ceilings, in contrast to large spaces of greater height, and if spaces did not interrelate to provide the user with a sequential experience of moving from one to another. Monotony would also result if all interiors in a given building were of the same colour, material, and textural quality. Man needs variety and change.

The manipulation of space is a matter of both aesthetic and functional consideration. A small entrance vestibule in a building is needed to keep out wind and cold or heat and rain, yet it is equally important in providing a visual transition from outdoors to the interior of the building. The sheltered sleeping alcoves in early cave dwellings served not only to express man’s desire for smaller and more intimate spaces for personal use but gave protection from draft or cold.

Much in our man-made structures is built of natural materials, and it must be remembered that these materials have natural colours and textures that usually are superior to anything man can create artificially. Competent designers are very much aware of the innate qualities and textures of all materials, especially natural ones. For instance, a sensitive designer would choose a simple oil finish on wood to bring out the beauty and quality of the grain rather than use the once-fashionable high-gloss finish that tended to obscure and change the texture. Textures are important not only for their appearance but also for their sense of touch, and for their effect on light absorption or reflection. Abrasive surfaces or very rough plaster would obviously be unpleasant to the touch and possibly dangerous in an interior, depending upon the use the interior is intended for. Textures can evoke feelings of elegance (such as silks) or informality (such as rough, tweedy materials).

Light, both natural and artificial, is one of the most important design elements, but unless surfaces are appropriate in colour and texture, the control and effect of light will be lost. The beautiful quality of space in a Gothic cathedral is very much related to the handling of light. The source of daylight, high overhead or filtered through stained glass, creates exciting patterns of light and shade and a variety of intensities and pools of light. This same principle can be used in all interior spaces, and contemporary interiors often have skylights or high windows to provide variety and changing patterns of light. Artificial lighting is equally important, and, again, the same considerations of highlights, good overall illumination, and variety are important.