They're a kind of postcard printed from the 1930s to the 1950s, mainly,
that have a surface texture that looks like linen. They usually feature
very bright colours. The Curt Teich Co. of Chicago is especially
strongly associated with linen cards.
Yes although as a percentage of the total number of 1940s cards the
"valuable" ones are uncommon. Depends on how you're defining "valuable"
of course. It's hard to say which types are valuable but very fine
"linen" cards can be worth something, espec...
I believe "halftone" is more properly reserved for monochrome images,
and that (B) is a "chromolithograph", which is the same sort of thing,
but using coloured dots (cyan, magnenta, yellow) to allow for the
mechanical creation of colour images. "Legi...
3 is a collotype, not an RPPC. The recommendation to look for dots is a
bit simplistic as it incorrectly assumes that all printed cards were
printed with halftone processes. Collotype and other gelatin-based
processes were also frequently used, despi...
