darktable preset inspired by FerraniaP30

What the style changes

The style converts the photo to black and white with less weight on red, then adds deep shadows, silvery highlights and fine grain. The film itself is described on the Ferrania P30 film page. All figures below come from renders made with darktable-cli 5.6.0 at 1000 px, measured in CIELab, compared with darktable’s base render.

• Gray with less red. A color calibration instance named “N&B” mixes the channels with estimated weights (0.215, 0.245, 0.540). They start from the Pan F Plus 50 weights (0.249, 0.243, 0.509), with less red as reviews describe. Ferrania publishes no spectral curve, so nothing was integrated from a graph.
• Contrast and deep shadows. The tone curve raises contrast (Lsd 30.7 → 32.6 on photo 1014, 14.3 → 18.0 on photo 0775) and lowers the darkest 5 % (L5 2.6 → 0.5, and 29.4 → 21.7).
• Restrained highlights. The L95 of photo 1014 stays about level (87.9 → 87.4). On photo 0775 it rises from 75.2 to 78.4.
• Sky and skin. The sky gets lighter (L 55.3 → 61.9), the sea slightly darker (38.4 → 36.8), skin darker (78.2 → 74.9) and a pink T-shirt darker (47.3 → 42.6).
• Fine grain. Coarseness 1000 and strength 16 place it between the Pan F Plus 50 and Fomapan 100 styles.
• A truly neutral gray. Chroma falls from 8.6 to 0.0.

Compared with nearby black-and-white styles

Same renders at 1000 px.

Measure	P30	Plus-X 125	Fomapan 100	Pan F Plus 50
Lsd, photo 0775	18.0	16.7	19.3	20.2
Lsd, photo 1014	32.6	31.7	34.0	32.9
L5, photo 1014	0.5	1.4	0.3	0.0
L95, photo 1014	87.4	88.1	89.5	89.9
Sky L, photo 0775	61.9	60.8	61.6	59.3
Skin L, photo 0989	74.9	67.7	71.1	65.9
Grain, sky of photo 0775, 2560 px	3.1	3.5	4.8	2.7

Grain is the standard deviation of the image minus its Gaussian blur (radius 4 px), measured on the sky of photo 0775 (0.3 to 0.7 × 0.05 to 0.3) in 2560 px examples.

Reading: the differences with Plus-X and Pan F Plus are moderate. They come mostly from lighter skin, more restrained highlights and deeper shadows than Plus-X. They remain subtle.

What it leaves alone

• Your base development. The style contains no exposure, no sigmoid or filmic and no LUT. Those settings stay as you made them.
• But it switches off your main color calibration. It contains two color calibration instances: a disabled one with no instance name, which replaces your main color calibration and switches it off (“as shot in camera”, CAT16, like darktable’s default), and the “N&B” instance that does the conversion. Why: an active color calibration running after the black-and-white conversion would tint the gray through chromatic adaptation.
• It also replaces your tone curve and grain. Their instances carry no name, so they replace any settings you had already made in those two modules when the style is applied from the lighttable or the darkroom.
• Your pipeline order. The style file carries no module order list.

Exporting with a style, or rendering with darktable-cli, adds every module as a separate instance; the disabled color calibration still switches off the existing one. Details are in Install and apply darktable styles.

Limits

• An interpretation, not a calibrated emulation. No film scan was used to tune the style.
• No datasheet curve. Ferrania’s guide has no characteristic curve, spectral sensitivity or RMS. The spectral weights and the tone curve are estimated from qualitative descriptions: they are choices, not measurements.
• Sources disagree on contrast (it depends on the developer) and on red sensitivity (panchromatic or close to orthopanchromatic).
• Skin gap. Reviews say skin darkens strongly. Here skin is darker than the base render (74.9 against 78.2) but lighter than in the Plus-X, Fomapan and Pan F Plus styles. Lowering red further would also darken the pink T-shirt (42.6), and the sources give no figures to size it.
• The developer. The film reacts strongly to developer and time. The style aims at a medium, contrasty look, not a specific development.
• The grain. darktable’s grain is procedural noise: it imitates the texture, not the shape of silver grains.
• The shoulder. The curve acts on an image already rendered by sigmoid, so the shoulder is approximate.

Tips

• Apply it early, before your own tone curve or grain settings, because it would replace them.
• Overexpose slightly when shooting for this look: Ferrania and reviewers suggest about 2/3 to one stop for shadow detail (see the film page).
• Back to color: switch the main color calibration back on and switch off the “N&B” instance.
• Installation: see Install and apply darktable styles.