In non-linear video editing, a dissolve is done using software, by interpolating gradually between the RGB values of each pixel of the image.
In narrative terms, the length of the dissolve is dictated by the mood or pacing the director or editor wishes to create.
For instance, in the opening sequence of Citizen Kane, the dissolves between the master shots are slow because of the pervading sense of morbidity Welles and his collaborators wished to create.
The device began to fall into disuse as filmmakers fell under the influence of the French New Wave directors and their innovative use of the jump cut and as the absence of a linear narrative became more common.
It is also sometimes held that the effect was best utilized in monochrome cinematography, where gradations of gray are mixed rather than possibly incompatible color tones.