The Use of Color in
Cement Tiles
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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.
[Illustration: Use of Color in Cement Tiles]
[Illustration: Color Tile Methods
1. Relief Tile.
2. Persian Relief.
3. Relief Line with Mold Color.
4. Relief Line, Majolica Color.
5. Intaglio Tile.
6. Sgraffito Tile.]
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