Ok, at the risk of starting a firestorm of people throwing stones at me here is the best video I can find. This video shows Recalescence because it is easier to see. As the blade cools you will see a darker line pass across the steel followed by a brighter line. Decalescence is the opposite. As a blade heats you will see the bright followed by the darker shadow. It will be harder to see because its in your forge but seeing the recalescence helps you know what to look for on decalescence. I explain things simply because that is how my mind works. Everyone hold your fire please.