one or more
scenes, after which, dressed as Darnley, he goes through the
synchronized action of that character. Synchronization--or harmony of
movement in time--of course demands that the action of both characters
be properly matched--to use a common and easily understood term--but
it will be seen that when the spectator watches only one character at
a time there is not the need for the _perfect_ synchronization of
action that is always demanded of the wide-angle double-exposure
scene, in which one man, playing two different characters, must face
himself and keep the action natural and convincing at all times.

Very few things in the development of motion picture art have advanced
so noticeably as this trick of portraying dual characters on the
screen by means of double exposure of the film. Theoretically,
it is extremely simple. There is a middle--or at any rate an
arbitrary--dividing line to the stage. A mask being placed over
one-half of the camera lens, the film is run through and the action of
Carton in a certain scene in which he is supposed to face Darnley is
taken. Careful track is kept of just what important moves he makes at
different stages of the count. Later, after he is made up as Darnley,
the first half of the lens is masked in the same way as before, while
the second half is exposed and the action of Darnley is gone through
with, with the gestures and other action properly timed to
synchronize with the action of his "double"--and that is all there is
to do. But the skill of the director is tested in his timing of the
moves of the characters, just as his knowledge of lighting and
backgrounds is tested so as to avoid showing the line where the two
differently exposed parts of the film join. Then, too, certain
directors have, of late, procured some "double" effects which well
deserve to be called wonderful, as when in a certain William Fox film
the two different characters, played by the one woman, are made to
meet and kiss each other most naturally.

To repeat, double exposure (to use the simplest term for this camera
trick) has made possible the writing of many stories for the screen
which a few years ago would have been rejected because of the
inability of the company to procure two people similar enough in
appearance successfully to portray the "doubles." No author with a
really fine idea for a dual-character story need hesitate to offer it
to the film companies today. But there is still enough addit