Quote Originally Posted by MattKing
The 160 speed for Portra might reflect the evolution from its predecessor, Vericolour, which if I recall correctly was 125. I think it would have been unlikely to have gone down, to 100, because so much of this film is (was?) shot with either flash or reflectors, and a loss of speed would not have been appreciated by the wedding/portrait photographers who use (used?) a lot of it.
You're right Matt, unfortunately I am old enough to have shot lots of weddings and mugshots on Vericolour it was indeed 125 ASA .