Murray -
I don't think I would worry too much about outgassing from paint used inside a camera.
First, outgassing mainly occurs during the time when the paint is "drying" - I put that word in quotes because the phenomenon is more involved that drying, but actually is also a curing process. That phenomenon is greatest when the paint is initially applied, and then declines over time. After some time (which varies between paints), all of the volatiles have dissipated and the phenomenon ends. In general, if the paint smells new, there is still some outgassing taking place, but when it stops smelling, it's about done.
Second, the nature of the outgassing varies with type of paint. Certainly, the concern would be greater with solvent-based paints (that category probably includes the alkyds), and it would be greatly diminished with water-based paints (the latexes). So-called "milk paint" is probably the least offensive.
Third, the degree of risk depends on the degree of exposure. That means that the longer the film remains exposed to the gas, the greater the potential risk. In most instances, the dwell time for film holders in a wooden camera is not more than a couple of minutes, and often only seconds.
So I would not be concerned about outgassing from the black paint affecting film for normal use if the camera is more than a few months old. And using a water based paint would certainly minimize the risk.