CHAPTER 5

The Use of Color in Cement Tiles

SUCCESSFUL COLOR IN CEMENT WORK is dependent entirely upon the use of mineral pigments in dry powder form. The lime action in the cement will nullify and disintegrate any color of a vegetable or chemical source so that no hue remains.

A LIMITED RANGE OF COLORS is therefore presented to the worker in Cement with which to secure results, but the list of colors described in the following paragraph is after all an elaborate one when compared with the few pigments with which the primitive and aboriginal potters produce most beautiful results in their wares.

PICTORIAL OR REALISTIC DECORATIONS ARE NOT DESIRABLE as Color Cement decoration and it is hoped by the authors that those who follow the technical direction of this book will be in harmony with the applied design principles set down in the last chapter; and that their color cement productions will be such that it will add correct line, form and color to this new handicraft. This will enable its growth among the art handicrafts to be without handicap or prejudices resulting from its use in incorrect design or application.

THE FOLLOWING COLORS ARE POSSIBLE in mineral colors for us in Color Cement: Black, Brown, Red, Dull Yellow, Blue, Green.

A Color Scale and Mineral Colors are as follows:

{ Germantown Lampblack Black or Gray { 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 { Roasted Oxide of Iron Brown { Burnt Umber { Metallic Brown

{ Indian Red 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.

MATERIALS FOR MIXING COLORS are as follows: Two sizes of small sable-hair brushes, a palette knife (or putty knife), several small dishes, a spoon, a fine-mesh sieve, and a piece of glass.

TO MIX THE COLORS proceed as follows: Place a little of the desired color on the glass, to this add dry cement reducing the color intensity to the desired strength. Portland cement being gray will do this harmoniously. To this add a few drops of water until the color is of the desired consistency.

The color should always be tested on a tile surface and dried in the sun to determine final color, adding color or cement to the wet mixture to correct the color. Where a tint of color is wanted a white cement should be added instead of Portland cement.

To produce a plain surface color on tiles, the desired quantity of color is mixed and strained, to eliminate all coarse particles. The mixture may be sifted while dry or strained after the cement has been added.

THE USE OF WHITE CEMENT should be limited because white cement is not as durable as gray cement and because its setting qualities disappear as it becomes older more rapidly than gray cement. If perfectly fresh it can be used with good results and produces a more brilliant color when mixed with the colors than when gray cement is used.

TO APPLY THE COLOR either in the mold or to the surface of the object after it is removed from the mold, the color should be applied with a brush.

AS A TEST COLOR PROBLEM use an incised pattern plaster mold and the colors may be planned for the incised tile as follows: Working from a color sketch, mix up colors to match and after the plaster mold has been water soaked it should be oiled by dabbing the brush up and down on the surface. If the brush is stroked it will not leave enough oil on the surface and the color will stick to the tile. Next drip the cement color from a brush with a shaking motion. The various colors are thus placed in each of the partitions of the mold and after drying for fifteen minutes is backed with a layer of plain cement and sand and allowed to set.

When the tile is released it will contain different colors between the incisions and a thin wash of an additional color may be added to fill the incisions.

COLORS CAN BE MIXED one with another while dry or when wet to produce other shades. Violet will be produced by the mixture of mineral orange and ultramarine blue.

PLAIN SURFACED TILES MAY BE COLORED by pouring in a thin layer of color combined with neat cement and then backed up with a concrete mixture. Mottled and variegated color surfaces may be secured by first spattering or dropping drops of another color into the mold before the color mixture is poured in. Or the plain cement or concrete tile can be removed and covered with a color layer which will be dull or glazed in finish.

A PLAIN TILE TO BE APPLIED WITH COLOR should be placed in water immediately on being removed from the mold, and allowed to remain there for a quarter of an hour, before applying the color. When taking the tile out of the water do not let the fingers come in contact with the surface to be colored. Let the tile stand a few minutes to drain, before applying the color. Then a thin layer of neat cement mixed with water is applied. Next place a spoonful of the color upon the surface of the tile, slightly shaking the tile while level, then pour off the surplus color as it overflows the edges. If bubbles occur the surface should be recoated for the bubbles will break in the drying, producing a defect. To prevent bubbles, the color should be stirred with the spoon slowly so as to avoid the arresting of air which produces the bubbles. The point of a pin will often help to dissolute the bubbles if used immediately after the surface is coated. When satisfactorily coated, place the tile carefully in a tray and add water until it reaches a little more than half way up the side of the tile. Be careful that water is not splashed or dropped on the newly coated tile, for this will ruin the surface and necessitate doing the tile again. The tile should remain in this water for four or five days, water being added when it has become absorbed or evaporated.

TO COLOR AN INCISED DESIGN the plaster cast from the original becomes the mold for the color cement tile. The plaster, having become thoroughly dry, is shellaced with one or two thin layers of shellac and after drying for one or two days is ready for use with color cement.

It is then oiled well but not so that surplus oil remains on the surface. A dry brush will be good to use for removing surplus oil. The color having been mixed to harmonize with the previously prepared color sketch, one of the color mixtures is taken up with a brush and dripped with a shaking motion onto the correct area, which in an incised design is divided into spaces. If a drop of color falls where it is not wanted, take a clean brush and pick the color out of the space, after which a little oil should be brushed carefully into the space to renew that which was removed with the misplaced color. If any color falls onto the back of color already placed do not worry over it as it will not appear on the finished surface.

ANY COLOR NEXT TO A FILLED SPACE may overlap the previously filled space as only that color touching the plaster surface will be visible when the tile is removed from the mold and is finished.

AFTER COVERING THE ENTIRE SURFACE WITH COLOR let it remain for half an hour before backing it up with the concrete mixture, as otherwise the weight of the concrete may force gravel particles through the thin color deposits and mar the face of the color design.

TO COMPLETE THE TILE remove after two days, and place in water after the edges and slight faults have been corrected. It should harden in water for several days and then dry in a cool place after which it can be waxed or finished in other ways.

ANY OF THE PREVIOUS PROBLEMS described in the methods for producing tiles in plain cement can be carried over into this chapter and color added to the texture finishes in cement and concrete and many interesting finishes developed.

OLD COLOR AND CEMENT or dried cement color should not be used. Mix up only enough color for immediate use as any color not used fresh after mixed with cement cannot be used again and should be discarded.