Louis Comfot Tiffany early in his career became very interested in the production of colored iridescent, innovative art glass. In literature published by Tiffany he stated that research in the development of these glass making techniques began in 1872 in New York. Tiffany had enlisted the help of Italian trained Venetian glass producers who he hired. In 1878 Tiffany established the firm Louis C. Tiffany & Co. which specialized in the creation of elaborated decorated interiors for very wealthy residential clients and commercial institutions. One element which Tiffany incorporated in to the these projects were the use of iridescent glass tiles. They were used as fireplace surrounds , in decorative screens and wall ornamentation. The tiles were molded and made in various sizes with different decorations. The colors of these tiles included translucent opalescent and greens, iridescent blues and golds, as well as solid colors such as blacks, reds and oranges with fabulous swirls of color. Subsequently Tiffany produced additional glass tiles for use in lamps and decorative objects. Some of these tiles included scarobs, turtleback tiles, iridescent glass prisms, and linenfold glass (which resembled folded linen).
Between roughly 1892 and 1924 blown glass made into vases and bowls was produced by the Tiffany Furnaces, in Corona Queens. People often talk about three general periods of glass production. The earliest period which roughly was between 1892 and 1900 was the period where the most experimentation was done both in form (shape), color, and application and special effects incorporated into the glass. The middle period was the period where the bulk of the Art Glass was produced. The late period,which spanned between 1916 and the end of the company in the late twenties was the period where more commercial and less innovative pieces were produced. Many of the pieces produced in the period were made in pastel colors.
Louis Comfort Tiffany was the artistic force and designer for all of glass. It has been stated that Tiffany would make very rough sketches for a piece and his artisans would then use the concept to created a more complex and detailed rendering of the piece, which eventually required Tiffany's approval before production was initiated.
In 1894 Tiffany registered his "Favrile Glass" for trademark and patent purposes. The term he coined actually did not refer to one color or type of glass, but many different colors and textures of glass which he used in the production of his various products including windows, lamps and decorative objects.
Most of the early blown glass vases were not signed. A paper label was applied identifying production by the Tiffany Glass and Decorating Company. In the earliest periods of production many pieces were numbered in sequence between 1 and 9999. In about 1894 pieces began to be numbered with a letter prefix, followed by a number. This used letters between A and Y (no Z). For example in 1894 prefix A and B were used, !895 prefix C and D...until about 1905 with prefix W and Y. In this early period roughly 2 letters were used per year. Following this a number followed by a suffix was used (rougly one letter per year from 11906 to 1928). Some special notations including the use of X for experimental, EX for exhibition, o(small) for special order, A-COLL for pieces made for Tiffany's personal collection.
Some of the types of glass that were produced were Decorated Glass, Agate, Cypriote, Lava, Paperweight, and Aquamarine glass.
Decorated Glass was produced throughout the periods. The decoration could vary from several small lines on a solid backgroud to complex "king tut" decoration where almost all of the surface of the piece was decorated with random swirled lines. Some special styles of decoration include peacock feathers with eyes, zipper decoration, floral decoration with various types of stylized leaves and flowers.
Cypriote Glass, which was probably inspired by the appearance of ancient glass which had been unearthed after being buried for hundreds of years, and had taken on a roughened irridized surface. The surface often had crater like irregularities resembling the surface of the moon.
Lava Glass which is a dark bluish black background with applied three dimensional designs in gold which simulated the flow of lava.. These are very rare and valuable
Agate glass, which was made to resemble agate with many banded and shaped layered colors. Often these vases were faceted to created even more unusual effects with color.
Paperweight glass which was essentially transparent glass with floral or geometric colored designs had been created internally to give the appearance that the design element was under water or floating within the glass, like the paperweights we use on our desks
Aquamarine glass which is similar to paperweight glass with internal decorations of often aquatic subject matter like fish, which appear to be swimming in the glass.
Cameo glass, which was a technique where when the glass was made one color layer was applied on top of another. In the finishing process the design was created by cutting into the top color to reveal the underneath color cut in often floral techniques.
In the collecting of Tiffany Glass size and color does matter. The most common color is gold, followed by iridescent blue and green. Rarer colors include red, yellow , orange and black. Rarer colors, more complex decoration and size definitely impact on value.