Bi- powder has the remarkable properties of appearing black when dusted on a light-coloured surface and appearing silver when dusted on a dark-coloured surface. You can use the same Zephyr® fiberglass brush and Bi- powder for 90 percent of your dusting requirements at crime scenes. The greatest advantage of using Bi- powder is that the lifted prints will be black when placed on a white backing card. This eliminates the bother of comparing latent prints with light-colored ridges on a black background against rolled prints with black ridges on a white background. It also means that only white backing cards will be needed. There is no need for black backing cards with Bi- powder.