The contrast of a black and white print is governed largely by the paper, not the negative. A single negative can yield a flat, muddy print or a crisp, full-toned one depending on how the paper translates its density range into reflected tones. Two families of enlarging paper offer different routes to that control: fixed-grade paper, manufactured in discrete contrast grades, and variable-contrast paper, in which contrast is set by filtration at the enlarger. The choice between them shapes workflow, consistency and the kind of local manipulation possible under one exposure.

How Each Family Sets Contrast

Fixed-grade paper carries a single emulsion whose contrast is fixed during manufacture. Historically these papers were produced across a numbered series from grade 0 (soft, low contrast) to grade 5 (hard, high contrast), with grade 2 or 3 treated as normal. A negative is matched to a grade: a low-contrast negative is printed on a hard grade to expand its tonal separation, a contrasty negative on a soft grade to hold detail in both shadows and highlights.

Variable-contrast paper carries a blended emulsion of differing colour sensitivity on one sheet. As Ilford’s technical literature for its Multigrade papers describes, the emulsion behaves as a low-contrast component responding primarily to green light and a high-contrast component responding to blue light. Yellow filtration favours the soft green-sensitive layer and lowers contrast; magenta filtration favours the hard blue-sensitive layer and raises it. A single box of paper therefore covers the full grade range, selected by filters or the dialled colour head of the enlarger.

Filter Grades and Exposure

Ilford’s Multigrade filter set is numbered 00 to 5 in half-grade steps, twelve filters in total, the lowest number being the softest. Because the two emulsions differ in speed, the effective paper speed changes with filtration: the harder magenta settings generally demand longer exposures than the softer yellow ones, so a change of grade usually requires a corresponding exposure adjustment. Manufacturers also publish an ISO range figure, derived from the log-exposure range a grade will print; a negative whose density range measures 1.30 log units, for example, corresponds to an ISO range of about 130, guiding the printer to the matching grade.

Trade-offs in Practice

Fixed-grade paper offers consistency and economy of process. With no filtration in the light path it is simpler to expose, slightly faster, and less prone to safelight fogging, and grade is never set by accident. Its limitation is granularity and supply: contrast moves in whole grades, and the once-complete 0-to-5 ranges have contracted sharply, with several manufacturers now offering only one or two grades.

Variable-contrast paper trades that simplicity for flexibility. Half-grade increments allow finer matching to a negative, and a single sheet supports split-grade printing, in which one exposure is made through a soft setting and a second through a hard setting. Because the emulsion response curves are not linear across grades, the two exposures combine to give independent control: the soft exposure governs highlight separation, the hard exposure governs the depth of the blacks. That separation, exploited during dodging and burning, is the principal reason variable-contrast paper has become the darkroom standard.