I've discussed a little about how I buy first-day-of-issue caches to supplement the customized postcards I create--particularly when they apply to film stamps that were issued before I began collecting. This means that I've done my fair share of research poring through old stamp catalogs to see what kind of stamps (US and otherwise) are out there.
The earliest stamp I ever found that specifically referred to the art of cinema was this 1944 US release, commemorating the 50th anniversary of motion pictures. Presumably, they use the creation of the first film (Fred Ott's Sneeze) in 1894 as a benchmark, though the first public cinema, a Kinetoscope parlor in New York City, also opened that year. Because it's such an important philatelic issue given my "topical" interest, I've picked up more caches for that issue that I would've ordinarily.
You'll notice that some of these were postmarked in LA and some in NY. While there is now a central office that handles First Day of Issue postmarks for any newly released stamp, it still appears that back then, some post offices would take it upon themselves to have a special postmark because of the demand and popularity of these kinds of collectibles.
All these caches were mass-produced, so none of them is unique and I've seen other examples of the exact same illustration at subsequent conventions. The more rare examples would actually be the bottom two, since they incorporate a later issue (The Films of 1939) to supplement the original--something which I'll be doing more of with samples in my collection in the future.
Even decades later, this 1944 stamp (Scott #926) remained very unusual and cinema-themed releases were few and far-between, outside of the occasional movie star. So because the pickings were really slim for many years, it actually seemed
conceivable that I could collect every cinema-related stamp made
Then, the market exploded with souvenir sheets (usually from third world countries) specifically targeting collectors with appetites for celebrities and movie stars, and this ambition of mine became prohibitively expensive. So while my collecting habits were two pronged for a while, I no longer worry about any new cinema stamps that are outside the US. There are too many and the souvenir sheets are designed to be pricey.
But what I do have, I'll begin to post here, too, even though the cards and postmarks are my primary emphasis.
The Beau Geste and Stagecoach stamps are Scott #s 2447 & 2448 respectively.