Quote Originally Posted by BMbikerider View Post
At least since 1962 which was the 1st time I used it. Wikipedia dates it before that but I can go back no further.
The current formulation certainly hasn't been around since 1962, which I believe was what the OP was asking. Today's Tri-X is noticeably different from what I used in the 70s and early 80s.

From the Wiki link the OP posted:

"In 2007, Tri-X was extensively re-engineered, receiving the new designation 400TX in place of TX or TX400, and became finer-grained."