Hall's Hanging Tiles are glazed of different colours and fixed to walls by a nail in each tile driven into the joints of the brickwork, and are used to cover walls where light is important, as in areas, or for cleanliness, as in dairies.
Encaustic Tiles are those in which the colours are produced by substances mixed in with the clay - not printed on after the tile is made.
Those tiles which are ornamented by inlaid patterns of different colours are made in the following manner: -
The clay used is first very carefully prepared - mixed with the colouring matter, and "slipped," that is passed through fine muslin or silk sieves; boiled in the slip-kiln until it becomes plastic, wedged, that is cut up into pieces, which are dashed against one another to drive out the air and consolidate them; and aged, that is kept for several months, during which fermentation goes on and organic matters disappear. During this time the wedging should be repeated at intervals. After this the clay is slapped, that is, cut up by means of a wire into long pieces, which are kept always in the same direction. This consolidates the mass and preserves the grain.
Each tile generally consists of three layers : - The face, which is a slab of very pure clay of the colour required for the ground of the pattern; the body, which is of coarser clay; and the back, to prevent warping, which is formed with a thin layer of clay different from the body.
The clay for the face is cut into a pat about 1/4 inch thick, and as much larger in area as will allow for contraction in burning. It is then placed upon a plaster-of-Paris slab, upon which the form of the inlaid pattern is left in relief. The face clay pressing upon this receives an indentation corresponding to the form of the pattern required.
It is then backed up with the body of coarser clay, and the thin layer to form the back.
At this stage the maker's name is stamped on the back, and also a few holes to make the cement adhere to the tile when it is set.
Slip clay of the different colours required, according to the design, is then poured into the different parts of the indented pattern on the face.
After this has become hard, the superfluous clay is carefully scraped off, leaving it only in the parts originally indented so as to form the pattern.
The raw clay tiles are then trimmed, carefully dried, baked in ovens, protected from smoke, etc., by being arranged in large fireclay jars called seggars.
"A class of pseudo-encaustic tiles is now being largely made, in which the colour, which should be burnt in along with the clay, is merely applied as a transfer printed pattern on the surface.
"Such tiles are frequently coated in the glass oven with a transparent fritted glaze, and serve for flower boxes, wall tiles, and such like purposes.
"To give them the appearance of having true inlaid colours, the edges of these tiles have frequently a little colour applied to them to represent the depth of the insertion of the coloured clay."1