Although white portland cement has been around for along time, it is only comparatively recently that designers have begun to use it to achieve the striking color effects that white concrete can so ably supply. The product's major asset, aside form its striking architectural beauty, is its ability to remain white throughout its life. White concrete, obviously, is not a surface treatment that can deteriorate with age. One of the major uses for white concrete lies in providing the matrix for exposed aggregate and terrazzo finishes. The range of visual effects possible here is almost limitless since the white mix can be adjusted virtually at will to complement and bring out the natural color of the stones. Experimentation can give big rewards since the matrix color can serve either as a blank unobtrusive background, or be made to create an entirely new overall color effect. It is here that the use of pigments has its main value; a white cement is always preferable as the basis for a colored matrix, both because it is uniform in color to begin with (and therefore makes sample and remix matching easier), and because it allows a larger range of colors to be obtained. Even a full black color is best derived from the use of a white cement. White cement has one possible disadvantage that greatly concerns builders and designers. This is the possibility that white concrete may show dirt accumulation more readily than its gray cousin, regular portland cement concrete. Dirt accumulation may be a bit more of a problem, but the experts say proper clean-up inside and proper drainage outside should take care of normal dirt or contamination troubles. White concrete for normal architectural use will shed all but the worst industrial contamination during a rainstorm. Indoors, the recommended treatment for white concrete surfaces is simply a daily sweeping, damp mopping once a month, and scrubbing with a clean rotary machine every tow or three months.