I would like to beg the indulgence of all and the help of any resident
photographers on the List.

My Sweetheart has been sorting through the wartime (WW II) photos of her
father.  The ones which were in an album are amazingly fresh looking, but the
dozens of glossy, black and white snapshots which were stored in boxes have curled
severely.  Is there a good and proper way to flatten them?  I've weighted
some of them with volumes of the Britannica, but after a couple of weeks they
have not flattened very much.

Also, is glassine of mylar the better envelope material for long tern photo
storage?

Thanks one and all,
George