A Color Scale and Mineral Colors are as follows:

Black or Gray — Germantown Lampblack
Carbon Black
Black Oxide of Manganese
Black Oxide of Copper
Blue — Ultramarine Blue
Oxide of Cobalt
Yellow — Yellow Ochre
Chromate of Lead
Orange — Mineral Orange
Green — Chrome Oxide of Copper
Carbonate of Copper
Brown — Roasted Oxide of Iron
Burnt Umber
Metallic Brown
Red — Indian Red
Venetian Red
Mineral Turkey Red
Raw Iron Oxide

THE SUCCESSFUL USE OF COLOR IN CEMENT depends entirely upon the true proportion of color to the cement. No exact rule can be quoted as colors vary in quality in different localities. Experimenting only can solve the correct proportions. Also, anything that will nullify the action of disintegration upon the color by the lime in the cement is desirable. The Petroma Cement Colors made by the American Crayon Company of Sandusky, Ohio, fulfill these requirements for the craftsman, and will aid in successful schoolroom results, avoiding loss of time and waste of material.

COLORS MAY BE GLAZED, MAT OR DULL FINISH according to how and when it is placed on the cement tile. Each finish requires different treatment and the easiest is the Dull Finish.

THE DULL COLOR FINISH is produced when the color is dropped or placed into the mold and concrete or cement is used as a backing. This results in the color drying in the mold with a dull finish next to the plaster mold surface and is exposed when the cement casting is released from the plaster mold.

THE GLAZED COLOR FINISH is more difficult to produce successfully and is secured only in that color that is placed onto tile or pottery surfaces after the cement surface has partially hardened. A tile design or pattern may be cast in a mold and after it has come out of the mold it is dried for an hour and then placed in water. If the surface to receive color has been roughened or lines scraped into it when first released from the mold and the cement slightly soft, the color will adhere even more surely. We know that metal craftsmen often roughen the surface of metal where enamels are to be placed and fired in, to insure more perfect attachment, and a similar treatment to the cement will do likewise for the cement color. When the cement tile has been removed from the water and surplus moisture shaken off a little plain neat cement is placed on the surfaces to be colored and to this the color in thin paste form is dripped from a brush. No back stroke is possible without injuring the finish. Finish each section and then leave it alone.

A SAFE WORKING METHOD is to place the tile in shallow water to avoid any part becoming dry while the color is being applied. A pan or shallow dish will serve the purpose.

THE MAT FINISH is produced the same as for the Glazed Finish excepting that the tile is placed in water immediately after it is removed from the mold and placed there for a few minutes only. The surface is treated otherwise similarly to the glazed process and this results in the color being dull in finish.

HARDENING IN WATER should be done with all tiles and the dull and glazed finished tiles should be set in a pan of water without letting the water reach the decorated surfaces.

A COLORED SKETCH should be made in every instance where color is to be applied to cement.