[potentially NSFW] Back in the old days, pre-videotape and videocam, where did people get their sexy home movies developed?

Now of course, there are cell phones and tablets with unlimited storage for when people want to make their own sexy videos.

But back in the pre-videotape days, there was only movie film that had to be sent out to be developed, which meant that your anatomy was on display to anyone at the film developing lab.

How did this work? You must have had to send them out of town – you didn’t want the local film lab doing the work. Were there labs that specialized in ‘adult film developing’? Were they trustworthy? Did they keep copies for themselves? Etc.