conrad_hoffman, wrote 16X, ha! Not happening.
Actually 300x already achieved 300x, 16x is a piece of cake
You can look up old issue of American photograpy:
Philip Priedell in in 1946 November issue of American Photography.
Friedell used a two bath developer containing Benzotriazole.
He use Dupont sound track film with very low film speed--Weston 8
to take picture with this low speed film and developed in his two bath
developer, he got result equivalent to Weston 300 to Weston 460
a amazing speed boost of 300x to 450 x