Slabs - Truly Protective or Harmful?

[KMayUSA6060]

Originally Posted by TanksAndSpartans

This thread has some good technical discussion at the end: http://net54baseball.com/showthread.php?t=91156&page=2

So based on that, it would seem that all of the slabs are acid-free?

[trdcrdkid]

Believe it or not, this issue -- of cards being potentially damaged by clear materials meant to preserve them -- was being written about by Jefferson Burdick in the early 1940s. The first item below appeared in the October 1, 1941 issue of Card Collectors Bulletin, in which Aywon Exchange discusses the use of cellophane envelopes mounted on album pages to hold cards, and Burdick adds an editor's note recommending instead the use of Crystal Mounts, which were made for blocks of stamps. (I assume Burdick accidentally omitted a "not" when he wrote that they "are said to be injurious to paper and printing".) The second item below appeared in the next issue of CCB, dated December 1, 1941, and in it Burdick warns that ordinary cellophane can damage cards, but that cellulose acetate, which was used to make Crystal Mounts, is safe. The last item, which I previously showed in my post on James Colkitt and the auction of his collection, is from two issues later, the issue of April 1, 1942. It describes how Colkitt was using Crystal Mounts on scrapbook pages to mount his collection of 19th century tobacco cards; Burdick heartily approves, and I suspect that either he told Colkitt about this method, or Colkitt read about it in Burdick's CCB articles and decided to try it.

In any case, the idea of mounting collections of cards in an album, protected by a clear layer of protection, pretty much faded away after the 1940s, though it never totally went away. Plastic sheets made for baseball cards came on the market in the mid-1970s and immediately became very popular, but it turned out that the first generation of plastic pages contained PVC, which could damage cards over periods of many years. I remember around 1980 when this became widely known in the hobby, and everybody was scrambling to get plastic pages with "No PVC".

[steve B]

Oddly enough, cellulose acetate isn't really used anymore. The primary use was photo film. Under certain conditions it can degrade and give off acetic acid as it does. It also shrinks.

Crystal mounts were the thing for the better stamps when I was a kid, but haven't been used for a long time now.

Interesting to see that the national archives used it even knowing it wasn't all that great. It's probable there just wasn't anything better. Polypropylene and Mylar didn't come along until the mid-late50's,

[Jobu]

Sometimes properly slabbed cards are still damaged by the holders.

[sterlingfox]

They absolutely get damaged in slabs - especially in SGC slabs (even one's with a functioning gasket!)

[Leon]

Bryan- It is sort of hard to tell if the card was damaged, to me, by those scans. Is it more obvious in person?

For me, slabs protect the cards better than no slabs....

.

[icollectDCsports]

Originally Posted by trdcrdkid

Plastic sheets made for baseball cards came on the market in the mid-1970s and immediately became very popular, but it turned out that the first generation of plastic pages contained PVC, which could damage cards over periods of many years.

Remember the vinyl smell of those '70s - early '80s era sheets?