So a further question is when it's worth it to submit a film scan rather than reshoot on digital, and I think in the case of the test image of the peppercorns above, I have to admit that it would have been much easier just to reshoot. In the time I think it would take me to scan and work on that image, now knowing what they want, I was able to shoot 23 new digital images of similar subjects (an hour or two of work all told), all of which were accepted without question, so for this kind of subject, I think it makes more sense to reshoot.
I did keyword the peppercorns shot as a Kodachrome image, since it has a characteristic Kodachrome look, but I'll be surprised if it gets any hits for that. Another interesting thing about that shot is that I picked it out of a group of macro tests I did one day with various lenses and methods (dedicated macro lenses, reversing rings, enlarging lenses, bellows, etc.), and for this purpose, I didn't look too closely at the slide, but just selected it based on a general impression without a loupe, and it wasn't the sharpest slide in the bunch. I made it using a 100mm/f:3.5 Medalist Ektar that I adapted for 35mm.
On the other hand, I have a collection of hundreds of bird photos on film, and those involve spending a lot of time in the field waiting for the birds, the light, the seasons, etc., and I think I will be scanning those for submission rather than trying to create a whole new collection of digital bird photos. And then there are images made with view cameras or panoramic cameras or medium format that couldn't be easily replicated with a small format DSLR, so those it would make more sense to shoot on film. I suppose that if I was more into the gritty 35mm B&W look, I'd do that on film as well, but my "gritty" aesthetic is more 4x5" Weegee style--still film but another thing.