Aside from that, since an 8x10 uses
sheet film, one would expect that the shutter mechanism doesn't have an
'expose-once' lock, like you'd find on a 35mm - so what's the point in
messing about with the dark slide? Surely that will be more likely to induce
camera shake than a cable release.

What a terrible ignorant post. The bellows and rig is fixed. You simply close
the shutter for multi exposures. Common stuff if you actually make money taking
pics. Don't guess if you don't know....which you don't.

RB