A set of simple silicon filters could dramatically improve the quality of X-ray images produced in hospitals and at airport checkpoints. The technique provides a more detailed picture of fractured bone and could help airport security scanners distinguish plastic explosives from harmless substances. X-ray images normally reveal the way different materials, including body tissue, absorb X-ray radiation. Strongly absorbing areas are white and weakly absorbing ones black. But finer details are often lost in a fog caused by areas with intermediate radiation-absorbing ability.