Recently there has been discussed strobe effects in the movies.
I mentioned this to a collector friend who among other things collects
phonographs, and movies.

He showed me a modern strobe for electric phonos.  There is a disc
similar to the old style.  After you start the phono, with the disc on
the turntable you take a small plastic box the size of a pocket pager.
Aim it at the disc and a red light comes out showing you the correct
speed.  It appears to stop the disk, not unlike a timing light for a
car.

He then set up a movie for me to see.  It was a 16 mm soundie of the
movie, "The Music Box (Movers?)", with Laurel and Hardy.  I couldn't
figure out why it wasn't called Piano Movers; maybe the script was
written when large upright disc music boxes were popular?

The story is about a wife that buys her husband a player piano for his
birthday.  First scene is in the store where there is a shot of the
salesman and wife listening to a small player.  Which looks like the
roll is going bottom to top.  This is a distant shot.  After many goof
ups that only Laurel and Hardy can do, they finally have it playing in
the living room of her house.  The roll is shown in a close up for the
title of the roll, "Patriotic Songs", in that shot it shows it going
forward as it normally does.

I agree with why the effect happens, 24 frames per second in filming
gives this effect.  This movie, however, made me curious if the
distance of the shot made a difference, or had they when the watched the
rushes of the close-up saw that it obvious that it was going the wrong
way, and then filmed it with the play in rewind?

Just thought I'd add this for food for thought.  My friend didn't know
the answer either.

Dave Brown