When is it obligatory to perform ghusl when the colors of menstrual blood progress from red, then brown, then yellow, then white?

Menstrual blood is thick, dark, and has a distinct odor. The brownish and yellowish discharges are considered part of menstruation as long as the woman is within her customary period. A woman should not hasten until she sees the white discharge (al-qassah al-bayḍā’). If her usual menstrual days have ended and she has performed ghusl (ritual purification), then any brownish or yellowish discharge she sees afterwards is not considered anything, because it is not part of menstruation. The summary is to perform ghusl upon seeing complete dryness or the white discharge.