Interior design is the arrangement, decoration, and furnishing of the interior spaces in residential and nonresidential buildings and in such other enclosed structures as ships and aircraft. The term interior decoration has often been used interchangeably with interior design, although the former refers more specifically to the trades concerned with the ornamental aspects of interiors (wallpaper, upholstery, drapery, and so forth). Trained professionals who plan interiors generally prefer the latter term to describe their field. PRINCIPLES OF INTERIOR DESIGN The design of interiors is influenced by the related and overlapping professions of \Tarchitecture\t, which deals with all aspects of buildings, including their basic structure from the foundation up, and \Tindustrial design\t, which deals with the design of factory-made products, such as appliances and vehicles; and by various specialized fields, such as \Tfurniture\t design and textile design. The interior designer is concerned with the planning and layout of interior spaces not already fixed by the architect, the selection of furniture and other appointments, and the arrangement of the lighting, colors, and rugs or carpets--all of which are orchestrated to create a space that will be useful, pleasing, and comfortable. In the case of a private home or apartment, this work often is done by the actual occupant, although a professional designer may be consulted or entrusted with the entire job. Almost all buildings used by a wider public--including the interiors of offices, hotels, hospitals, restaurants, and similar structures--are handled by an interior designer with college-level or art-school training and with substantial practical experience. Although some architects design the interiors of their buildings, more commonly the architect plans a building shell and leaves the interior details to be determined later. This procedure almost invariably is followed in constructing apartment buildings, which will be inhabited by tenants with varying tastes and needs, and office buildings, whose floors normally are open spaces that will be divided into rooms and planned in detail to suit different occupants. Ideally, the interior designer will consult with the architect while a building is still in the planning stage, so that the basic layout and the locations of stairs, elevators, and plumbing can be arrived at jointly. In buildings with repeated standard elements, interior-design work often comes first--planning a hotel room that will be repeated dozens or hundreds of times is a logical first step in designing a complete hotel. In the case of an already existing building, the interior designer must be aware of the problems that may arise in moving doors, walls, or stairs and must understand the relation of design work to the plumbing, electrical, heating, and air-conditioning systems. Some types of interior-design assignments--offices, health-care facilities, and aircraft and spacecraft interiors, for example--are so specialized as to require designers or design forms that concentrate solely or chiefly on their execution. Functional Considerations Every project must begin with some consideration of the function of the space to be designed. Even those spaces with a seemingly simple, straightforward function can present the designer with a complex set of problems. An ordinary residential living room, for example, must accommodate a wide range of activities--from entertaining and visiting with friends and family members to reading, relaxing, listening to music, and watching television--each of which has its own requirements. In most cases the designer faces both the practical problem of tailoring the space to fit its function within an allowable budget and the more subtle problem of making the atmosphere and character of the space "feel right" to its users. Whether a space should seem active or calm, formal or casual, cozy or spacious, simple or grand, depends on the different geographical, economic, and social contexts within which it functions. The crowding that may seem appropriate in a city nightclub would be irritating in an airport terminal, where a feeling of tension and enclosure is anything but welcome. Similarly, a California beach house of luxurious dimensions presents a totally different challenge from an East Coast urban apartment. Aesthetic Elements Once having ascertained the functions that an interior must serve, the designer turns to the vocabulary of expressive elements with which to work. The basic size and shape of a space generates certain reactions: a low space can be snug, a high space impressive, a wide and low space oppressive. These relationships, or proportions, are basic to making a space feel right to its users and to defining its aesthetic qualities. A more subtle corollary to the idea of proportion is the concept of scale, or the relationship between the psychologically perceived size of spaces or objects and their real dimensions. Whereas, for example, big and bulky furniture will seem to overpower a small room, tiny furniture will seem lost in a vast hall. Color and light, taken together, influence very powerfully the aesthetic impact of an interior space. The suitability and attractiveness of bright, fresh colors is obvious in many situations, but dark, heavy colors can also be effective when a solemn or dramatic interior is called for. Bright lighting can be cheerful and active; dim lighting, dignified and calming. The textures of materials--slick and shiny, soft and rough, and so on--also suggest different feelings; surface patterns can be small and busy, large and dramatic, or smooth and uncluttered. The Design Process The planning of an interior design usually begins with the designer's developing a written statement about the intended uses of the space and its specific requirements. This so-called programming stage is followed by the execution of sketches or preliminary plans showing proposed floor-plan layouts and rough perspective views. More-formal perspective drawings, called renderings, and scale models may also be used. Next come color charts displaying actual samples of materials and catalog illustrations depicting the furniture, light fixtures, and other appointments selected. Once all the design decisions have been made and approved, the designer develops working drawings to delineate the exact construction and placement of all elements. Lighting may require a special drawing, as may the plumbing and mechanical systems. The preparation of budgets, selection of contractors, placement of purchase orders, and supervision of all work follows. Selection and purchase of small accessories or even works of art may be part of the complete project. HISTORY OF INTERIOR DESIGN The formalized design process described above is a recent development. Until modern times, most interiors were of the kind now called vernacular: that is, unplanned groupings of the normal everyday objects of the time. Throughout history, however, important buildings, both public and private, such as palaces, churches, temples, and civic monuments, have displayed more carefully thought-out interiors, although prevailing currents in architectural styles and craft techniques have always dominated interior design. Evidence from Ancient Times The complex civilizations of the ancient world each developed a distinctive approach to architecture and interior design. Because furnishings and decorative elements are perishable, however, it is difficult to reconstruct the building interiors of antiquity. A partial exception is ancient Egypt, whose funerary customs included filling tombs with domestic and decorative objects along with descriptive paintings and carvings. The details of ancient Egyptian interiors thus preserved include beds, chairs, and chests of highly refined design and rich decoration. Mural paintings and painted relief enlivened these interiors, which also were adorned with such accessories as alabaster containers, glassware, pottery, and fine gold and silverwork. (See \TEgyptian art and architecture\t.) Modern knowledge of ancient Aegean and Greek domestic design is based chiefly on vase paintings, although remnants of brightly colored wall paintings survive from the elaborate palace at \TKnossos\t (c.1700-1400 BC) in Crete and from other centers of \TAegean civilization\t. Greek vases dating from the Classical period (5th-4th century BC) depict refined and elegant furniture that is almost modern in character. During the Hellenistic period (late 4th-2d century BC) the Greeks perfected the art of \Tmosaic\t, which was used to decorate the floors and walls of homes and public buildings. (See \TGreek architecture\t; \TGreek art\t.) Ancient Rome imitated and elaborated on Greek interior design. The famous \TPantheon\t (2d century AD) in Rome has retained its rich marble-inlay interior decoration, and carved stone benches in theaters and forums provide clues about Roman furniture design. Most fortunate of all for modern students of interior design was the preservation under layers of volcanic ash from Mount Vesuvius of nearly complete villas at \TPompeii\t and \THerculaneum\t. The elaborate wall paintings and floor and wall mosaics used to decorate these luxurious homes, which date from the 1st century AD, demonstrate the Roman adoption of Greek models. (See \TRoman\t \Tarchitecture\t; \TRoman art\t.) The Far Eastern civilizations of China and Japan developed design traditions that had little in common with ancient Western practice. Traditional Chinese buildings, executed almost exclusively in wood, featured roofs supported on columns, with walls independent of the main structure. Decorative details were concentrated on the richly carved and painted brackets between columns and roof beams; formally arranged furniture, although restricted to a few simple types (principally tables and chairs), was often elaborately carved. (See \TChinese art and architecture\t.) Japanese interior design, although influenced by Chinese tradition, diverged in the direction of austerity and simplicity. The traditional Japanese interior is based on the modular arrangement of floor mats (tatami); sliding screens (shoji) are used as walls, making possible a highly flexible interior. Furniture is minimal and portable. The simple, geometrically elegant Japanese interior influenced modern Western design in part because of the affinity between its graceful functionalism and the predominant bias of 20th-century modernism. (See \TJapanese art and architecture\t). Medieval and Renaissance Europe Outside of the Byzantine and Islamic civilizations, which inherited the Greco-Roman tradition of mosaic decoration, early medieval Europe produced little of note in interior decoration. Most people lived in small, primitive dwellings; the \Lcastle\ls and manor houses (see \Thouse\t, in Western architecture) of the nobility were designed to facilitate defense rather than enhance comfort. The so-called great hall, the most important room in the castle, functioned as the kitchen, dining room, and even bedroom of the occupant. Aside from wall hangings and \Ltapestr\lies, which were introduced as a form of insulation in the Romanesque period (AD c.1050-1200), furnishings and accessories were few and simply designed. During the late-medieval period (mid-12th to the 16th century), manor houses gradually shed their fortified character and became multiroom residences of increasing luxury and comfort. Both furnishings and architectural details grew more ornate, and elements borrowed from Gothic cathedrals, including stone and wood tracery and \Tstained glass\t, came into wide use. Wood paneling first appeared in late-medieval interiors. The humanistic, secular culture of Renaissance Italy (c.1400-1600), greatly influenced by classical antiquity, introduced a new strain of luxury, grandeur, and ornamentation into Western interior design. In Italian Renaissance palaces and villas, as in their Roman prototypes, rooms were arranged symmetrically around a central courtyard. Moldings and other details of classical origin adorned doors, windows, fireplaces, cornices, and ceilings; mural paintings, tapestries, or stone inlay appeared on walls. The Medici Palace in Florence and the Farnese Palace in Rome exemplify the Italian Renaissance design style, which was spread throughout Europe by such expatriate artists as Leonardo da Vinci and Giacomo Barozzi da Vignola. The great 16th-century CHATEAUX of France--BLOIS, \TChambord\t, \TChenonceaux\t, and \TFontainebleau\t--have interior spatial arrangements and decorative details quite similar to the Italian models of the previous century, although adapted somewhat to French taste and the dictates of a colder climate. In England the Renaissance era is identified with the \TTudor style\t (1480-1540), the \TElizabethan style\t (1558-1603), and the \TJacobean style\t (1603-25), all of which incorporated Italian motifs into basically late-medieval forms. Baroque to Neoclassical Periods The rich elaboration, sumptuous decoration of walls and ceilings, and emphasis on complex spatial patterns characteristic of the baroque period (c.1600-1750; see \Tbaroque art and architecture\t) originated in such opulent interiors as the \TDoge's Palace\t in Venice and the \TPitti Palace\t in Florence. During the reign (1643-1715) of Louis XIV (see \Tstyles of Louis XIII-XVI\t) the French designers Jean \TBerain\t, Andre Charles \TBoulle\t, Jules \THardouin-Mansart\t, Charles \TLe Brun\t, and Andre \TLe Notre\t adapted Italian baroque themes into an elegant, more austere style whose grandeur is apparent in such notable interiors as those of the Palace of Versailles (see \TVersailles, Palace of\t). The French style greatly influenced 18th-century German and Austrian designers, whose principal monuments include the \TSchonbrunn Palace\t near Vienna and the \TWurzburg Residenz\t. English baroque evolved along different lines. Under the guiding genius of Inigo \TJones\t, who emulated the classical style of the Italian architect Andrea \TPalladio\t, 17th- and 18th-century English designers, such as Sir Christopher \Twren\t and Sir John \TVanbrugh\t, executed harmoniously proportioned interiors notable for their restrained and elegant decoration. The fine wood-carving of Grinling \TGibbons\t embellished the interior of Jones's \TWhitehall Palace\t and other structures of the day. During the reign (1715-74) of Louis XV, French designers and architects turned to a more delicate style of decoration that featured smaller-scale rooms, lighter furniture, the use of free-curved forms, and a toned-down color scheme. This \Trococo style\t was influenced heavily by Chinese decorative motifs introduced through the importation of Chinese porcelain, lacquer, and other ornamental objects. Rococo artisans soon produced great numbers of objects in the fanciful style known as \Tchinoiserie\t. The spread of rococo ideas to Germany is evident in the interiors of the \TAmalienburg Pavilion\t and the \TNymphenburg Palace\t, both near Munich. The rococo style was followed by the development, during the reign (1774-92) of Louis XVI, of French \Tneoclassicism\t in art, characterized by a return to naturalism and simplicity, the use of straight lines and semicircular curves, and a revival of the classical vocabulary of ornamentation. A classical sense of architectural ornament and furniture design is particularly apparent in the works of Georges \TJacob\t, Jean Henri \TRiesener\t, and Robert \TAdam\t in England. Allied to but significantly different from French neoclassicism was the \TGeorgian style\t of 18th- and early-19th-century Great Britain. Classically inspired masters, such as Richard Boyle, 3d earl of \TBurlington\t, and William \TKent\t, along with the more baroque-minded James \TGibbs\t, incorporated into the Georgian interiors a neoclassicism abetted by lighter proportions in ornament and furniture. This was also the age of the great furniture designers Thomas \TChippendale\t, George \THepplewhite\t, and Thomas \TSheraton\t, as well as of the ceramics of Josiah \TWedgwood\t. During the late Georgian period the neoclassical \TGreek Revival\t style and \TRegency style\t dominated British design. Origins of Modern Design The first half of the 19th century was marked by a wide variety of design styles, as artisans sought to come to grips with the advent of the Industrial Revolution. In the United States the utilitarian simplicity of colonial interiors (see \Tcolonial styles in North America\t) gave way to the British-inspired neoclassicism of the \Tfederal style\t and the furniture designs of Duncan \TPhyfe\t. Simultaneously, the eclectic and grandiose \TEmpire style\t took hold in France under Napoleon I (r. 1804-15). German and Austrian designers, on the other hand, preferred the solid, functional furniture and small-scale interiors of the \TBiedermeier\t movement. The British \TVictorian style\t, the most eclectic and diverse of all 19th-century design movements, ranged from the romantic \TGothic Revival\t style espoused by Augustus \TPugin\t to the crafts-oriented and individualistic \TArts and Crafts movement\t founded by William \TMorris\t. Toward the end of the 19th century, \TArt Nouveau\t emerged as the first concerted attempt to create a truly modern style of design. Characterized by rich, curvilinear forms and natural motifs, Art Nouveau found expression in the decorative glassware of Emile \TGalle\t and Louis Comfort \TTiffany\t and the architecture of Hector \TGuimard\t, Victor \THorta\t, and Charles Rennie \TMackintosh\t. The Art Nouveau style was followed in the 1920s and '30s by \TArt Deco\t, a form of popular design that featured sleek, highly stylized geometric ornamentation. Prime examples of Art Deco decoration include the lighting fixtures and glassware of Rene \TLalique\t and the interiors of the \TChrysler Building\t and \TRadio City Music Hall\t in New York City. Modern Design The modern movement in interior design, grounded in Louis \TSullivan\t's axiom that "form follows function," reached maturity after World War I at the German \TBauhaus\t under the direction of Walter \TGropius\t. The Bauhaus architects, along with Frank Lloyd \TWright\t in the United States and \TLe Corbusier\t in France, sought a design vocabulary free of reference to the historic past and faithful to the realities of modern industrial production. Wright continued to use some abstract ornament, but the other modernists favored plain surfaces, simple details, and industrially produced building materials, such as glass and steel. Proponents of the new style designed light and simple furniture, usually geometric in form and built with chrome tubing, meant to complement open, often asymmetrical interior spaces. This so-called \TInternational Style\t, as developed more fully in the work of Alvar \TAalto\t, Marcel \TBreuer\t, Charles \TEames\t, and Ludwig \TMies van der Rohe\t, has dominated 20th-century design since the 1920s, although traditional and historical design styles have retained some popularity. In recent years, however, architects and designers have experimented with ideas that are less rigidly logical and more experimental in character--a movement often given the generic name of postmodernism (see \Tpostmodern architecture\t). John F. Pile Bibliography: Ball, V.K., Architecture and Interior Design (1980); Calloway, S., and Jones, S., Style Traditions (1990); Friedman, A., et al., Interior Design, 3d ed. (1982); Madden, Chris Casson, Interior Visions: Great American Designers and the Showcase House (1988); McClelland, N.C., A Pictorial Encyclopedia of Home Decoration, 2 vols. (1989); McCorquodale, C., History of the Interior (1983; repr. 1990); Pevsner, Nikolaus, The Sources of Modern Architecture and Design (1969); Pile, John, Interior Design (1988); Tate, A., and Smith, C.R., Interior Design in the Twentieth Century (1986); Thornton, P., Authentic Decor (1984).