Trying to find a Sci-Fi movie, probably from the 50's or 60's

Question

I’m trying to identify a movie I saw when I was very young. It was a “Saturday Matinee” playing on one of the local stations, and I likely watched it in the late 60’s. So I expect that the movie is from the 50’s or 60’s. I watched it in black and white, but it could have been a color movie on a black and white set.
I clearly recall a scene where scientists enter a lab and some see something move past them in a blur. Later in the movie, they come upon themselves in the same lab where they appear to be frozen and not moving. Then they notice that their “other selves” are moving, just almost inperceptibly slowly. They are encountering themselves but at a completely different time scale. Unfortunately, I don’t recall much else about the movie, just the idea that they encounter themselves once with the others flashing past, and again seemingly not moving at all.

If this rings any bells with anyone, I’d love some pointers to try to track this movie down.

Answer 1

"The Time Travelers"(1964)?

It was in color, and involved scientists traveling to the future. Near the ending, they encounter themselves in the lab and realize they're stuck in a time loop. Here is a section of the plot synopsis from Wikipedia describing this scene.

The survivors return to the lab, where they make a strange discovery. Their past selves are still in the lab, yet to pass through the portal, but they appear frozen. Through some error, the travelers are experiencing time at an accelerated rate; the rest of the world, including their past selves, is moving in extremely slow motion. Their only option is to travel to the date the portal had briefly been set to before being set to 2071 A.D., a date over 100,000 years in the future. But the screen is dark and what lies ahead is unknown.

I can't find that scene, but here is a trailer from YouTube:

I guess it's actually NOT a trailer, but the entire movie in 3 minutes!