[en] The sample volume in diamond-anvil pressure cells suitable for X-ray powder diffraction studies is very small (≤ 100 μm across). The resulting low signal-to-noise ratio has made it very difficult to obtain useful results with monochromatic angle-dispersive techniques, and the alternative white-beam energy-dispersive techniques have limited resolution and generally give unreliable peak intensities. The situation has been transformed recently by the introduction of the image-plate two-dimensional detector, which allows angle-dispersive methods to be used with a greatly increased signal and improved powder averaging. A short review is given of this development, the experimental techniques, and the principal advantages, particularly as found in results obtained at SRS Daresbury over the past two or three years. (au) (18 refs.)