Presumably this means that antimony forms a crystaline structure like ice does, becoming larger when solidifying, or am I misinformed?
BBCW, I once worked with a local rag press and have a dim recollection that "printer's metal" was specially formulated so that the alloy had a slight expansion as it solidified, as water does; it was this property that produced beautifully crisp print. Whether it was solely due to the antimony content I can't remember, but I'm sure you could glean info by googling "printer's metal"/"type metal" and/or antimony. I do recall that, although vast quantities of scrap offcuts were lying around during the preparation for the print run, they were meticulously collected and recycled, as the alloy was expensive and criminal charges were brought against people who tried to sell it to scrap metal merchants or those merchants who bought it.
TJ, thanks for the compliment. It occurred to me while I was reading earlier parts of the thread that some might be confused by changes of meanings, as well as by simple appearances. I had thought that the change from antique (lead-containing) pewter to britannia metal (and thus modern pewter) had occurred in the middle of the 19th century and was surprised to see the relevant Standard hadn't come into force until 1974. I had never associated cadmium with pewter and I suspect that most people's experience of it would be cad-plated metal items. These routinely have a dull grey lack of sheen, not unlike pewter's appearance when it hasn't been cared for over a long period of time; I hesitate about calling it a patina but that is probably the proper term for the surface of weathered pewter.