The tomb would have been dark. Don’t know why you’re so confident in identifying Nicodemus. Rather than the other male being John, my money would be on Joseph of Arimathea, whose tomb it was and whom Scripture specifically credits.
You might be very right. I think Nicodemus stuck in my mind from some literature I read a long time ago. I just checked on Wikipedia and they identify him as Nicodemus with the face of Caravaggio himself. Wouldn’t Joseph of Arimathea have been old?