Abstract
General ideas of usages of anormalous dispersion effects are given in the limit of kinematical diffraction. They are categorized in two groups. One is to utilize phase effects due to imaginary part of anomalous dispersion. The other is to change the contrast of atoms which show dispersion effects. The latter is normally done by changing the real part of anomalous dispersion at the lower energy side of absorption edge where the backgroud is much lower than that of higher energy side.
