If the color sinks in too rapidly and becomes lost, the under surface is too wet and the painting should be delayed for several hours or until the color applied lays upon the surface properly.
THE CEMENT SLAB IS TRANSFERRED TO THE METAL TRAY as soon as it is removable from its surface. In fact, a good way is to move the wood or glass under support with the cement slab upon it and place the whole combination into the tray. If the sides are well set the retaining walls can be removed, and as soon as the whole layer is set enough so as not to be dissolved by water, water is poured in the tray until it comes half-way up the side of the cement slab. This will prevent the whole slab drying prematurely as the water will supply all that is needed. If the water becomes absorbed more should be poured in. After it has remained in the tray for a week, it may be withdrawn and permitted to dry gradually. Wet cloths around it will prevent too rapid drying.
WHEN WORKING UPON THE SURFACE, the surface should be completed as the space is covered, avoiding returning to work upon any part after it has commenced to set. If the surface has formed a shell or thin layer and reworking breaks this shell, the color in that section will not harden properly. It requires direct, confident handling of the subject, and reworking of the surface such as the painter in oils is accustomed to is not possible with color cement.
A WHITE CEMENT SURFACE can be formed over a cement layer and when this is nearly dry thin washes of color cement may be used onto the surface similar to working with water color. The white cement will absorb the color easily and parts of the design may be worked in opaque or solid colors.
A DARK WORKING BACKGROUND may be used by mixing a layer of dark blue, brown or green. A layer of black can also be used. Brilliant colors can be brushed or dripped into this so that they sink and become a part of the dark surface without being in relief. A slight shaking of the surface or the tray will produce this amalgamation of colors.
WATER SHOULD NOT REACH THE COLOR SURFACE until after it is entirely dry. To avoid water splashing onto the surface from the tray it is the best policy not to pour water into the tray before the painting is completed and only when the tray is to be left undisturbed.
TO CONNECT THE COLOR CEMENT MURAL with the building wall, the space to receive it should be well moistened and covered with neat cement which is well worked into the surface. The back of the cement mural is similarly treated and the two cement surfaces are pressed together and held in position by a brace or support until thoroughly dried. The space or border edge around the panel should be filled in with cement at the same time.
