Fold pattern/direction

[Sunsanvil]

Should all US 1-sheets exhibit the same fold pattern/direction or are there variations out there?

[CSM]

Should all US 1-sheets exhibit the same fold pattern/direction or are there variations out there?

Well there are tri-folded one sheets out there.  And of course a lot depends on what has happened to a poster once it got into someone's fold-challenged hands - that's when you see all sorts of interesting configurations (like being folded outside in!)

[Sunsanvil]

When folded, should you end up with artwork showing, or the backside?

[CSM]

When folded, should you end up with artwork showing, or the backside?

You would want the artwork on the inside (not showing).  Many posters have stamps or other important information on the blank backside. Unless it is a double-sided poster of course but those should almost never be folded... 

[erik1925]

I actually have several that were originally machine folded with the artwork showing on the outside. One I was able to check right off the bat is the US OS for The Eyes of Laura Mars (1978).