Flotsam said:
I just assumed that it was the same Polymax emulsion on either a single or double weight base.
It is -- but like coating a film emulsion on a different base, and unlike (as I've been corrected on) coating the same Tri-X R or Plus-X R (you're right, Helen, it's the reversal version in Super-8 -- but that version is also sold in 16 mm and 35 mm; it's just the negative version that isn't in Super-8) on the same base and slitting/perfing for different formats, the single and double weight have to be coated separately. That means it costs relatively more to carry two weights in the same emulsion for paper than it does to carry multiple film formats of the same emulsion/base combination in film, and the single-weight has to stand or fall with less support from other base products that use the same coating.
Yes, there is a cost associated with making Super-8 cartridges -- but injection molded plastic parts made in quantity can cost less than a penny each in the size of cartridge shell halves; the film in the cartridge costs at least 10 times what the shell does, at the manufacturer level. Cost of the film, though, is dependent on how much is coated at once, how long it keeps, and how much is sold.
Paper is more of a niche item than film, precisely because film is used for motion pictures (which burn a huge amount relative to our still image use); paper doesn't keep as well as film (especially modern papers with developer incorporated), and the single-weight Polymax is as much a separate product from other papers as T-Max 100 on glass plates was from T-Max 100 4x5 film. Continued coating of TMX emulsion on 4x5 sheet film did nothing to keep up production of the glass plates.
