Here is the panel we used for color back in those days:
The joystick in the upper left was for blacks ("lift"), the one on the bottom was for mids ("gamma"), and the one on the upper right was for highlights ("gain"). The center shaft of the joystick increased or decreased relative level, and then you would slide the joystick around towards green, blue, or red (or inbetween), depending on what balance you wanted.
The section on the left was for audio (optical sound or mag track on the film). To the right of the joysticks are the transport controls, which include "inch up" and "inch down" controls for framing (because 35mm film sometimes slips a perf or two). The far right side was the TOPSY computer: telecine operation system (I think). You had buttons to create a new color "event" by pushing one of the far right buttons, which would basically be where there was a cut or transition in the film being run on the telecine. The controls at the top were for rippling and manipulating the color list, which was extremely primitive. The first TOPSY had no GUI display at all, but they eventually added a "VDU" (video display unit) so that we could see a crude graphical representation of the color list, about 10 shots at a time.
The computer could only hold about 600-700 color events before it would freeze up. It was technically possible to save the color list to a floppy disk by the telecine itself, but it was extremely erratic and unreliable. Many times, we'd record the color-corrected film out to videotape, then once that was good, we'd hit the button to save to disk... and the entire thing would crash and we'd lose the entire session. As long as we'd gone to tape, it was OK. If you hadn't... you'd have to start all over, which was sad and horrible.
The Mark IIIB Rank-Cintel Flying-Spot Scanner looked like this:
The controls on the bottom left side I think were for shading and sizing, and I think the controls on the bottom right were the Digiscan that stabilized the video output basically like a time-base corrector. The controls in the center adjusted the amount of voltage on the CRT tube that provided a light source for the scanner. If the light level changed over time, the machine would drift and change color -- meaning what you color-corrected at 9AM might look about 15% different by the time 3PM rolled around. They generally tried to keep the telecine rooms very, very cold to try to stabilize the machine's performance. We rarely ran film on reels (unlike the machine pictured in the brochure), and instead had platters which could run print or IP or camera negative, each of which required very specific "front end" adjustments very similar to what we do with camera raw files today.
By about 1984, a much better color-correction system called AMIGO, which was much more refined, had fixed secondary controls, variable saturation, and could store positional changes (XY Zoom) fairly reliably. Amigo was such a hit, it was still being used all the way through the late 1990s. Rank came out with several better scanners, each more stable and producing better color than the last, but by the late-1990s, the Philips Spirit CCD scanners took over that market pretty quickly, just as HD and 2K came in.
Color correction has not changed as much as you might think in 30 years: clients are still picky, colorists still turn knobs and try to dial in changes to placate the DP and director, time and budget are major factors, and there are still things you can't really fix but you can always make somewhat better. There are things I miss about those days, but I much, much prefer the degree of control we've had in the last 10 years to everything that came before it.