By
the 1840s, encaustic tiles were made entirely with almost-dry
clay using the dust-pressed method. This served to eliminate
the possibility of staining the body of the tile with other colors
and permitted the use of more colors on a single tile. Thus,
an encaustic tile can sometimes be dated according to the complexity
and the number of colors in its pattern. Red tiles with white
figurative patterns were generally the earliest, followed by brown
and buff colored tiles. In the 1860s, blue tiles with yellow
or buff patterns were popular, succeeded by more subtle color
schemes featuring a "chocolate" red with a soft grey.
By 1860, up to six colors were used in a single tile to form
a pattern. Toward the end of the century, white encaustic tiles
with a black or gold design were common, as well as tiles with
complicated color patterns of white, black, gold, pink, green
and blue. Encaustic tiles were decorated with traditional as
well as original designs. Some, particularly intricate, designs
were painted on the surface of the tile with opaque colored glazes,
instead of being inlaid. Most major tile manufacturers
sold many of the same pre-formed encaustic floor tile patterns
through catalogues. Encaustic tiles were produced in a variety
of sizes, mostly square or octagonal in shape, and almost any
design could be custom-made for a special purpose or to fit a
particular space. Historic, 19th-century encaustic tiles were
generally slightly less than 1" thick, about 15/16."
Cheaper tiles of lesser quality were also made of clay or cement.
These designs resembled those commonly found on encaustic tiles
but applied as a transfer printed pattern, or using a multi-color
lithographic or silkscreen process. These are still manufactured
and popular in many parts of the world.
Smaller, single-colored versions of encaustic tiles that, when
assembled together form a geometric pattern, are called geometric
tiles in England. However, in the United States they are
generally not differentiated from encaustic tiles. Based
on the geometric segments of a six-inch square, they were typically
rectangular, square, triangular or hexagonal in shape, and about
the same thickness as patterned encaustic tiles. Geometric
tiles were especially well suited for decorative borders, and
a wide variety of floor designs could be created with their many
shapes, sizes and colors--either alone or combined with patterned
encaustic tiles. The cost of producing geometric tiles was much
less than of encaustic tiles because each tile involved only one
type of clay and one color. By the end of the 19th century, over
60 different shapes and sizes of geometric tiles were available
in up to ten colors, including buff, beige or tan, salmon, light
grey, dark grey, red, chocolate, blue, white and black.
 Ceramic mosaic tiles were practical for structures like this Bath House, Hot Springs, Arkansas (1914-1915). Photo: Jack E. Boucher, HABS Collection, NPS. |
Ceramic mosaic tiles are essentially smaller versions of
geometric tiles (usually no larger than 2-1/4", and no thicker
than ¼") ranging in size from ½" to 2 3/16",
in square, rectangular or oblong, hexagonal, pentagonal and trapezoidal
shapes. Both vitreous and semi-vitreous mosaic tiles were available,
unglazed in solid or variegated colors with a matte finish, or
glazed in unlimited colors. Single, one-piece tiles were also
fabricated to give the appearance of multiple mosaic pieces.
This was achieved with a mold, which gave the appearance of recessed
mortar joints separating individual "mosaics".
Glazed Tiles
With the exception of quarry tiles, encaustic tiles, and some
mosaic tiles, most ceramic floor tiles are decorated with a glaze.
While unglazed tiles derive their color solely from the clay,
or from oxides, dyes or pigments added to the clay, the color
of glazed tiles is provided by the glaze, either shiny or matte.
Some potteries specialized in certain kinds of glazes and were
famous for them. The earliest and most common method of clay
tile decoration made use of tin-glazes which were essentially
transparent lead glazes. Tiles were either dipped into the glaze
or the glaze was brushed on the tile surface. Glazes were generally
made with white lead, flint, or china clays ground up and mixed
with finely ground metallic oxides that provided the color. Colored
glazes were commonly known as "enamels". Colors included
blue derived from cobalt, green from copper, purple from manganese,
yellow from antimony and lead, and reds and browns from iron.
An opaque glaze was created by adding tin oxide.
"Preserving Historic Ceramic Tile Floors" an Historic Preservation Brief
