Based on simulations similar to the ones used to generate high-quality Michel-Lévy charts, graphical representations of anomalous interference colours which are based on a linear model for the dispersion of birefringence are shown. In the charts, the path length difference ∆Γ D forms the ordinate, while the birefringence ∆Γ F − ∆Γ C forms the abscissa. Using these charts, many facts which are in principle well known, but whose justification requires rather abstract argumentation, can be grasped intuitively. The usefulness is shown by comparison with several photographs of anomalous interference colours observed either on wedges or conoscopically on various minerals and substances spanning the whole range of possible linear dispersion ranges quantified by different Ehringhaus numbers N. These diagrams may be of high pedagogical value in the teaching of polarisation microscopy and may complement the well known Michel-Lévy chart.