Split-grade Printing
Exposing a variable-contrast print twice, once through a soft filter and once through a hard one, to control highlights and shadows separately.
Measured in
seconds per filter
In depth
The soft exposure sets the highlight tones and the hard exposure sets the blacks, and because they are independent, dodging and burning can be applied to each stage differently. This gives control that no single fixed grade allows, and it makes local contrast a variable rather than a property of the whole sheet.
Examples in practice
A print given eight seconds at grade 0 then four at grade 5 holds both a bright window and a dark interior corner.