What B&W videotapes from 1956 to 1960 still exist?

[W3XWT]

I have a bunch of 1/2" carts recorded 1980-early 1990's in the Visually Horrid System format. I recently digitized one not played since 1980 and it was crisp as the day I'd recorded it. The only scare I had with it was when I thought it was over (by recognizing what I'd put on it to play for my grandmother), I was shocked to see stuff that I didn't recognize. There were color bars and a RMA test pattern, both sans ID. And, there was also some pretty decent TVDX out to about 250 miles. Only thing I could figure was my then 80-year-old grandmother, who had seen me TVDX'ing, decided to give it a try! Just, she didn't tell me! Funny thing is, in 1988 as we were getting ready to put her in a nursing home, I was bummed-out when I'd brought a VCR down to record the classic RCA test pattern of WIS-10, only to find they had super'ed on it a digital clock with the graphics quality of an Atari 2600! Still an early riser (farmer's wife for 53 years), she said "Don't worry. You have that already"... I didn't know what she was talking about. Even through the haze of Alzheimer's, she remembered. When I was watching the tape, I had a weird feeling. Not a creepy one per se. Then, I suddenly realized... it was my birthday on which I was digitizing that tape!

As for videotape, I believe storage is the key, I think. All of mine are tails-out, vertical storage and I've always watched the temperature and humidity. And, both the good and the cheap brands look as good as the say they were recorded. Very few dopouts, with most of those in the 5-10ms range at worst.