Hours which are past midnight are suffixed with next day date. In Panchang day starts and ends with sunrise.
Pratipada Shraddha is done for those deceased family members who died on Pratipada Tithi, including both Shukla and Krishna Paksha Pratipada.
Pratipada Shraddha Tithi is also considered suitable to perform Shraddha for maternal grandfather and grandmother (known as Nana-Nani). If there is no person to perform Shraddha at maternal home then doing Shraddha on this Tithi appeases souls of maternal grandparents. Even if death anniversary of maternal grandparents are not known then also Shraddha can be done on this Tithi. It is believed that performing this Shraddha brings happiness and prosperity at the home.
Pratipada Shraddha is also known as Padwa Shraddha.
Pitru Paksha Shraddhas are Parvan Shraddhas (पार्वण श्राद्ध) and auspicious time to perform them is either Kutup Muhurat and Rohina etc. Muhurat after that till Aparahna Kala gets over. Tarpan (तर्पण) is done at the end of the Shraddha.