All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.
The basic principle regarding what a woman sees of blood is that it is menses that prevents Prayer and fasting. As long as you see black blood that can be menses, then it is menses.
Therefore, don't pray and fast until you become pure after menstruation, as the Prophet, sallallahu ‘alayhi wa sallam, said, “The blood of menstruation is black blood (almost black) and recognizable (by women). If that is the case, then abstain from praying.” [Abu Dawood and An-Nasa’i, and Ibn Hibban and Al-Hakim classified it as Sahih]
Allah knows Best.