Broadcasting a color hardener with 60 pounds of medium brown per 100 square feet over a job's entire surface created this gorgeous slate look-alike. Two other browns — one "two shades darker, like a walnut" and the other "two shades lighter, like a tan" — were used to mottle the floor's color by putting "10 pounds here and 10 pounds there" and bullfloating it all in. Finally, a charcoal color release put the icing on the slate. "The different shades add the depth, " says concrete creator Lee Levig. "It makes the surface look three-dimensional."

Shown above is an integrally Buff colored overlay. The individual stone colors are created with three chemical stains: Jade, Harvest Gold, and Mission Brown. Stains are diluted at ratios of 3 or 4 parts water to 1 part stain and applied with a paint brush. One coat sealer is applied before grouting the joints and a second sealer coat after the grouting application. Installer: Charles leland, Sure Crete Design Products

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Coloring Stamped Concrete

One such method involves spraying a transparent colored liquid over a textured stamped surface and then applying a stamped concrete sealer. The colored liquid puddles in the low areas, where the concentrated color appears darker, while the base color shows through on the high areas producing a natural antiquing effect. If you want to antique individual stones different colors, brush on the same colored liquid in a circular or side-to-side motion. Both the concentration of the liquid and the way it's applied (spraying, brushing or both) will determine the final result, Sadleir notes.

When coloring and stamping, Rusk suggests using a 50/50 three-quarter aggregate stamp mix that is fly-ash free. "Fly ash slows concrete down but tends to bead up in black spots causing you to use more color hardener," Rusk says.

Breaking the mold
Ken Freestone, director of technical engineering for Elite Crete Systems Inc. in Valparaiso, Ind., says some people are getting away from mixing a color hardener with a powder release because it's so time consuming and not very practical for interior jobs. Instead, they're turning to acid stains or styrenated acrylic for extra color.

"Styrene blended with acrylic increases water resistance and produces more of a permanent solution vs. a coating," says Freestone. "With acid staining, you can get coloring on stamped surfaces within 24 hours vs. waiting a few days. It dries very fast and you don't have to allow three to four days for the moisture to evaporate."

Imprinted with the Lithotex Brick-Basketweave, colored with a dry shake Lithochrome Color Hardener Brick Red. It is accented with Lithochrome Antiquing Release Deep Charcoal. It is sealed with Scofield Cureseal Semi Gloss.

For a very mottled, realistic look, Freestone says you can first put down a reactive acid stain and then an antiquing acrylic to get various shades of high and low color.

"The drawback to chemical stains is that instead of covering an imperfection sometimes the stain will accentuate it," like effervescence or a stamp that is off kilter, says Charles Leland, general manager of SureCrete Design Products in Dade City, Fla. "Other times the results are killer."

Acid stains will produce a mottled look that is somewhat unpredictable. Because it depends upon a chemical reaction, you never know exactly what to expect. "But the sweet thing about working with overlays and acid stains is that ordinarily you'll get much more consistent results than with freshly poured concrete," Leland says. With the thinner overlay material, "the results of the acid stain will be more consistent because we control what's in the bag."