Mirrored Glass
Mirrored glass is glass that has been coated on one side with a reflective substance. From the 16th century to the 1840s, most mirrors were made through a process called "silvering." An amalgam of 75 percent tin and 25 percent mercury was painted onto the back of the glass. This was then sealed in place in the finished mirror. The amalgam is normally quite stable and is rarely disturbed unless the mirror is broken. Later mirrors substituted a silver nitrate solution for the tin-mercury amalgam.
Baroque Mirrors
Mirrors became major design elements during the Baroque Era. The Hall of Mirrors at Versailles set the standard for royal palaces and nobles' residences. Large mirrors were fabricated of relatively small pieces of glass that were joined together. Mirror frames followed sinuous shapes and were made mostly of oak and later of walnut and other woods. Frames were generally finished with gold or silver leaf that further enhanced the reflection of sunlight and candlelight.
Plate Glass and the Rococo
A major improvement in mirror design came just after the dawn of the 18th century. French craftsmen learned how to make large sheets of plate glass. Rectangular mirrors had richly carved mahogany or walnut frames. Gilded curlicues and seashells created a whimsical effect. Large mirrors could be placed over fireplaces or might become part of a general scheme of decorative boiseries, or wooden panels, that enlivened walls. English and American mirror makers learned the techniques of plate glass making in about 1770. Until that time, Anglo-American mirrors remained small.
Classical Elegance
The American and French revolutions ushered in an era of classical values and artistic tastes. Mirrors in the French Empire style are usually rectangular and bear little decoration beyond the gilt mahogany frames. English Regency examples are somewhat more elaborate, with gilded flowers and scrollwork at the tops of the frames. Neoclassical styles are all about harmony and order. Specific motifs mimick ancient Greek and Roman forms, such as the dentils, or "teeth," seen on mirror frames and architectural borders in the contemporary American Federal style.
Victorian Imitations
As the 19th century wore on, innovation focused more on industrial technique than artistic style. The Victorians--and their American and European counterparts--tended to imitate the design tastes of other periods. Various "revival" styles produced mirrors with heavy rococo and Renaissance frames. A Renaissance frame, for example, might feature the large factory-made plate glass of the 19th century surrounded by a frame decorated with 15th- or 16th-century motifs. A typical example might feature a large, carved grotesque, or animal head, as the focal point of the top of the frame.