- The release powder is the highlighter not the primary colorant in the concrete; coloring of the concrete may be achieved by using integral pigments or color hardeners. Which procedure to use should be determined by the final desired effect, conditions at the job site and preference of the designer. Integral colored produces a color through matrix while color hardener is a surface application. The advantage of integral color is that it colors through the thickness of the slab saves time and it makes for a cleaner finishing process.