As is well-known, characteristic complementary colors are obtained, if a lambda-plate is introduced in white polarized light. This fact is used for an unexpected characterization of nucleation occurring during short term shearing of supercooled melts of iPP. Blue specks show up some time after cessation of flow on a red background. The blue color indicates that these tiny nuclei are oriented in the direction of previous flow. With prolonged waiting these specks extend over a large volume. At their centers spherulites start growing.