George Lucas pulled some heat for not having credits at the front of Star Wars, IIRC. So mid 70s would be my guess.
Which was an anti union move on his part . Not providing people that worked on the film their due recognition since everyone could just walk out of the end credits.
Maybe an archaic concept today, even though it still exists, since movie credit details are readily available online with ease.
When they got long enough to cause a serious delay in the movie starting
Credits exist in both places though?
They were originally mostly or all at the beginning, as in several minutes of credits before the movie started. There were occasional exceptions where they had fewer or just a title screen prior to the 70s, but the vast majority had several minutes of credits before the movie started.
Star Wars kicked off popularity of pushing the credits to the end of the movie. Again, not the first, but the start of the popularity. Pretty sure Lucas received a fine for doing it as well.
Since then most movies tend to have a few credits at the beginning and the majority at the end. In my opinion this was inevitable. Star Wars had two good reasons to move them back from my perspective, it let the story start right away, and listing everyone involved with the special effects would have taken forever. The light credits, especially those overlaying the opening scenes is a lot better than the wall of text that was displayed before movies even started prior to the late 70s.
Credits followed by the opening crawl also would have been tedious.
and then there's a few films like robert rodriguez' we can be heroes, which has only his studio card at the very beginning and a title card two and a half minutes in. that's it. no opening theme, no opening credits at all, nothing. just movie. i kinda like it, actually.
The only time you want credits at the start is if you're running late to the cinema.
From my youth im used to some credits at the start. The big stars and such, but then the comprehensive list after. I have never known the comprehensive list to occur before the movie.
I think the tipping point where most credits were at the end occurred in the early 00s.
I think it's funny, nay, Alanis would call it ironic, that decades earlier trailers moved from the back to the front.
