While the old thin transparent tape is a possibility, the high probability is those old albums that were pre plastic sleeves that had a cardboard strip on the reverse side to prevent the coins from slipping through.
Hey guys, thought I'd share the coin that got me into unique patterns. I bought it raw and submitted it back when I really had no clue what I was doing really other than having good blind luck. Low and behold it came back 64! Now this one was most likely from tape. I have no idea how it was stored to get both sides but I love it...
There are lots of different types of folders and albums. Some of them were meant to help you save, not necessarily to collect or display your coins. They were often made from paper, and given out by banks. I wasn't able to find a picture of one with dollars (although, I know I've seen one before), but it would look something like this (not my picture):
@Cascade, those are some nice unique toners. I always wondered where the racing stripe came from.... @physics-fan3.14 , thanks for posting the visual of the album. I always wondered about that particular un-toned striping...now I know. Thanks!
These remind me of tab toning on classic commems. On commems, it's highly desired because it comes from the coins being in their original holders. Here's what the holder would look like (image from APMEX of all places): I've see them with different numbers of slots to hold coins: 3, 4, 5, and 6, IIRC. This was sometimes the result (image from Michael Kittle Rare Coins):
Yes, the tabs would have a different number of slots to correspond to the number of coins in the set. Sometimes the tab toning can be quite attractive (as yours). I like the ones from the center tab, that also has a dot in the middle. Sometimes, the tab toning can be terminal, and will be dark brown or black. The pattern is there, but avoid those coins.
Just a small clarification: I, unfortunately, don't own the pictured coin. The image is from http://www.kittlecoins.com/26593074.htm But, yes, definitely do avoid terminal (black) toning, generally speaking.