I have a question about micrograph of steel. In eutectoid steel, the pearlite exists as grains, within each colony the layers are oriented in essentially the same direction, which varies from one colony to another. The thick light layers are the ferrite phase, and the cementite phase appears as thin lamellae most of which appear dark. However in photomicrographs of a hypereutectoid steel (e.g.1.4 wt% C) , we can observe the proeutectoid cementite appears light. Why there is such a difference?