A Lap Dissolve is a technical term in film editing and is applied to the extent that the fade-in last shot of a previous scene is superimposed. The first shot of the next scene to appear (darkens) so that for a few minutes, both shots are seen at the same time. In general, the use of a dissolution is used to indicate that a certain amount of time has passed between two scenes.
These terms are used inter-changably to refer to a transition between 2 sequences or scenes. generally associated with earlier cinema but still used on occasion. In a dissolve a first image gradually dissolves or fades out and is replaced by another which fades in over it. This type of transition, which is known also as a soft transition (as opposed to the cut), suggests a longer passage of time than a cut.
Dissolutions are most common in classical cinema (see continuity editing), but are less used now. The device became obsolete as film directors came under the influence of French New Wave directors and their innovative use of jump cut and the absence of a linear narrative became commonplace. The influence of television reporting may also have caused the device to lose its claim to a contemporary feel.
A very well-known example of this is seen in ''A Place in the Sun'', directed by George Stevens.