Optical Effects: Dissolves
There are several ways of moving from one shot to another besides cuts. In a dissolve (or mix as it is often called) one shot gradually merges with another until it replaces it. Another way of moving from shot to shot is to fade out one and fade in another. These effects, and others like them are known as optical effects. Only a cut can actually be made by you. All the other transitions have to be produced by a laboratory acting on detailed instructions supplied by you. How are optical effects prepared?
In a dissolve one scene merges with another and gradually replaces it. In essence it is a fade out and a fade in superimposed. The outgoing shot starts to fade out and, at exactly the same point, the incoming shot starts to fade in. Dissolves can be printed when show prints are produced if the camera original film is neg cut in A and B rolls (See page 92).
As the shots gradually merge, where do you join the two shots in your work print? You should join at the centre point of the planned dissolve. And, most important of all, always ensure that there is an adequate overlap available.
Optical overlaps
When the camera original is matched to the cutting copy the outgoing and incoming shots must be overlapped so that a fade out and fade in can be superimposed. So, when you make your cut, remember this overlap and ensure that there is enough film left on either side of your cutting point. Dissolves can be long or short. With practice you find you can visualise the length of dissolve you want but 12, 24 and 48 frame (overall) dissolves are most common.
The length you use depends on the effect you want to produce and on the amount of overlapping original film that is available. The overlap should be half as long as the total length of the optical effect. So, if you have a 48 frame dissolve, you will need 24 extra frames on each shot at each side of the centre point at which you make your cut in the work print. When you join the centre point in your cutting copy mark the whole of the dissolve with the symbol shown on page 91. When the original is matched to the cutting copy the negative cutter will then overlap the outgoing and incoming shots on the camera original (see diagram). When the laboratory prints the two rolls they will start to fade out roll A and fade in roll B at the same point.
Remember the overlap
Join your cutting copy (A) at the centre point of the dissolve, checking first to ensure that there is enough overlap. This 40 frame dissolve requires a 20 frame overlap on the outgoing scene (C) after the centre point and on the incoming scene (B) before it.