The sliding door has led to another abuse in house-planning: the exaggerated widening of the doorway. While doors were hung on hinges, doorways were of necessity restricted to their proper dimensions; but with the introduction of the sliding door, openings eight or ten feet wide became possible. The planning of a house is often modified by a vague idea on the part of its owners that they may wish to give entertainments on a large scale. As a matter of fact, general entertainments are seldom given in a house of average size; and those who plan their houses with a view to such possibilities sacrifice their daily comfort to an event occurring perhaps once a year. But even where many entertainments are to be given large doorways are of little use. Any architect of experience knows that ease of circulation depends far more on the planning of the house and on the position of the openings than on the actual dimensions of the latter. Indeed, two moderate-sized doorways leading from one room to another are of much more use in facilitating the movements of a crowd than one opening ten feet wide.

Sliding doors have been recommended on the ground that their use preserves a greater amount of wall-space; but two doorways of moderate dimensions, properly placed, will preserve as much wall-space as one very large opening and will probably permit a better distribution of panelling and furniture. There was far more wall-space in seventeenth and eighteenth-century rooms than there is in rooms of the same dimensions in the average modern American house; and even where this space was not greater in actual measurement, more furniture could be used, since the openings were always placed with a view to the proper arrangement of what the room was to contain.

According to the best authorities, the height of a well-proportioned doorway should be twice its width; and as the height is necessarily regulated by the stud of the room, it follows that the width varies; but it is obvious that no doorway should be less than six feet high nor less than three feet wide.

When a doorway is over three feet six inches wide, a pair of doors should always be used; while a single door is preferable in a narrow opening.

In rooms twelve feet or less in height, doorways should not be more than nine feet high. The width of openings in such rooms is therefore restricted to four feet six inches; indeed, it is permissible to make the opening lower and thus reduce its width to four feet; six inches of additional wall-space are not to be despised in a room of average dimensions.

The treatment of the door forms one of the most interesting chapters in the history of house-decoration. In feudal castles the interior doorway, for purposes of defense, was made so small and narrow that only one person could pass through at a time, and was set in a plain lintel or architrave of stone, the door itself being fortified by bands of steel or iron, and by heavy bolts and bars. Even at this early period it seems probable that in the chief apartments the lines of the doorway were carried up to the ceiling by means of an over-door of carved wood, or of some painted decorative composition.[11] This connection between the doorway and the ceiling, maintained through all the subsequent phases of house-decoration, was in fact never disregarded until the beginning of the present century.

It was in Italy that the door, in common with the other features of private dwellings, first received a distinctly architectural treatment. In Italian palaces of the fifteenth century the doorways were usually framed by architraves of marble, enriched with arabesques, medallions and processional friezes in low relief, combined with disks of colored marble. Interesting examples of this treatment are seen in the apartments of Isabella of Este in the ducal palace at Mantua (see [Plate XIV]), in the ducal palace at Urbino, and in the Certosa of Pavia—some of the smaller doorways in this monastery being decorated with medallion portraits of the Sforzas, and with other low reliefs of extraordinary beauty.

The doors in Italian palaces were usually of inlaid wood, elaborate in composition and affording in many cases beautiful instances of that sense of material limitation that preserves one art from infringing upon another. The intarsia doors of the palace at Urbino are among the most famous examples of this form of decoration. It should be noted that many of the woods used in Italian marquetry were of a light shade, so that the blending of colors in Renaissance doors produces a sunny golden-brown tint in perfect harmony with the marble architrave of the doorway. The Italian decorator would never have permitted so harsh a contrast as that between the white trim and the mahogany doors of English eighteenth-century houses. This juxtaposition of colors was disapproved by French decorators also, and was seldom seen except in England and in the American houses built under English influence. It should be observed, too, that the polish given to hard-grained wood in England, and imitated in the wood-varnish of the present day, was never in favor in Italy and France. Shiny surfaces were always disliked by the best decorators.

The classic revival in Italy necessarily modified the treatment of the doorway. Flat arabesques and delicately chiselled medallions gave way to a plain architrave, frequently masked by an order; while the over-door took the form of a pediment, or, in the absence of shafts, of a cornice or entablature resting on brackets. The use of a pediment over interior doorways was characteristic of Italian decoration.

In studying Italian interiors of this period from photographs or modern prints, or even in visiting the partly dilapidated palaces themselves, it may at first appear that the lines of the doorway were not always carried up to the cornice. Several causes have combined to produce this impression. In the first place, the architectural treatment of the over-door was frequently painted on the wall, and has consequently disappeared with the rest of the wall-decoration (see [Plate XV]). Then, again, Italian rooms were often painted with landscapes and out-of-door architectural effects, and when this was done the doorways were combined with these architectural compositions, and were not treated as part of the room, but as part of what the room pretended to be. In the suppressed Scuola della Carità (now the Academy of Fine Arts) at Venice, one may see a famous example of this treatment in the doorway under the stairs leading up to the temple, in Titian's great painting of the "Presentation of the Virgin."[12] Again, in the high-studded Italian saloons containing a musician's gallery, or a clerestory, a cornice was frequently carried around the walls at suitable height above the lower range of openings, and the decorative treatment above the doors, windows and fireplace extended only to this cornice, not to the actual ceiling of the room.