Decorative concrete is a permanent application. Once a color or stain is applied to concrete, it cannot be changed. Additional colors may be added over the top, in some circumstances, yet this will only darken a color and will most likely not be your first color choice. However, the best time to achieve the exact look you want for your concrete finishes is before you start your project.
Practice your decorative concrete colors on garden pavers or other small concrete samples. Found at most hardware stores, these small pieces of concrete are lightweight and several can be purchased to experiment on for a small price. Remember, your concrete may still look slightly different than your sample piece. However, the color will be close enough to your original intentions.
When browsing through different decorative concrete products, see if the manufacturer creates samples that are available at a local store or available for purchase. These samples are often vary large and available in a variety of colors. Some stores may allow you to borrow the sample boards for a small deposit fee.
Practice your concrete technique on styrene boards. These thick, plastic boards are first primed with two coats of bonding primer. Then a light layer of concrete is added. Allow the concrete to dry fully. Add your decorative concrete treatment to the cement surface. Understand that fresh concrete may look slightly different in color than aged concrete.