the Middle Ages, bicoloured inlaid floor tiles were an essential
part in the decoration of churches, castles,
and noble houses. They were decorated with geometrical, floral
or figurative designs, and alternately set with plain tiles. They were widespread
in Northern Europe and particularly in France and in England, from
the XIIth to the XVIth century and even more lately, but today they
are nearly dwindled to vanish point. Archeologists are still finding out many
of them, and some collections are shown in museums.
The method was to fill the matrix of a stamped tile with white clay before it was glazed and fired, the two sections fusing during firing.
The techniques could be reconstituted by meticulous study of the objects, and with the help of some rare data reported in old handbooks describing the crafts of potter and tile maker.
The design of drawings and matrices (moulds), the operational chain from the treatment of clay until the glaze and the patina are delicate and long works.
The figurative themes (persons, plants, real or weird animals).
The geometrical themes, linear and circular set offer astonishing possibilities.
Heraldry is also widely used. In coats of arms, animals, plants, fleur-de-lys are found in all their forms.
The clay used for making up the tiles requires much preparation and refining. It can be mixed with ground-up fired clay which is called grog.
The tiles are shaped in a mould which is taller than the final tile (the tiles loose approximately one centimetre by side after drying and firing). The design is stamped using a matrice which is carved in relief, and leaves a print in hollow. The making of a matrices requires time and meticulousness.
After drying one can apply a glaze on the tile.
Firing is carried out at a temperature of more than 1000°C and lasts approximately 24 hours. The tiles will be finally "nourished" with linseed oil, and patinated with beeswax.
After stamping of the matrice using a hand-press, one proceeds to the parison : the cutting of the sides.
After a first time of drying, one fills the hollows with a liquid white barbotine. After a few days, one withdraws the barbotine surplus to find the clearness of the drawing, it is the most critical phase. The tiles are then stored in a dry place, turned over several times, and finally piled up by three or four, for the drying (during about one month).