One caution is necessary in the use of the cut-back—­do not use it as an excuse to digress.  Above everything else, when you have started the ball of your plot rolling, keep it rolling forward.  You must not switch back to some earlier scene for the purpose of picking up a point that you have overlooked.  Nor is it possible to go back and follow the characters who have been temporarily dispensed with.  If they reappear, it must be in a scene which naturally follows, and does not come with a sense of perplexing surprise.  Remember this:  When characters are reintroduced they must not have been too long absent from the plot-movement, but they must have been all the time consciously or subconsciously present in the mind of the spectator as being essentially in the story.

Unfriendly critics of the photoplay—­and there are some such—­have said some harsh things about “the mugging close-up and the nerve-wracking cut-backs,” nor have their criticisms been wholly without point and justification.  But only, of course, when these technical devices are abused by over-use.  Mr. Sargent has pointed out that the close-up of the silent drama is only another form of the spot-light used on the regular stage, and, similarly, the cut-back finds its duplicate in the “off-stage” sound-effects of the regular drama.  Instead of the “galloping horse” effects of the legitimate stage, we get on the screen the actual scene of the horseman dashing ahead.  But anything overdone is bad, and cut-backs and other similar devices are no exception to this rule.  Not only is our attention called to the fact that the writer or director is working a certain technical trick to death, but in following the story its working out is spoiled for us as a result of the very thing used with the intention of heightening our interest.

“Even Griffith, in his big production, ‘Hearts of the World,’ taxes suspense too far at one point,” says Mr. Sargent.  “So clever a trickster as he (and, like Belasco, he is more the artistic trickster than the artist) has failed to realize that suspense, carried too far, becomes first tiresome and then amusing.  This applies most directly to the single situation, but it is almost equally applicable to a situation strong in itself, but which is depended upon to yield suspense out of proportion to its value.”

And, since Mr. Griffith’s main suspense-producer has always been his self-invented cut-back device, the error of over-using this technical trick is made even more apparent by what this critic points out.  Here again a careful study of the methods of several different leading directors is your best guide.

10.  How Various Kinds of Inserts Are Used