darktable preset inspired by IlfordDelta 3200 Professional

What the style changes

The style converts the photo to black and white the way Delta 3200 sees color, then renders the film as most people shoot it: exposed at EI 3200 and push-developed, with blocked shadows, held highlights and heavy grain. What it is based on is detailed on the Ilford Delta 3200 film page. All figures below come from renders made with darktable-cli 5.6.0 at 1000 px, measured in CIELab.

• Gray from the film’s spectral sensitivity. A color calibration instance named “N&B” uses the weights of darktable’s own “monochrome | ILFORD DELTA 400 - 3200” preset, which darktable computes from the same Harman spectrogram. Our independent reading of the chart gives weights within 0.012 of the preset, and within 0.2 L* on the test photos.
  • Compared with a plain luminance conversion, and before any curve or grain, the sky gets lighter (L 55.2 → 59.6), while skin (79.3 → 73.0) and a pink T-shirt (47.8 → 44.8) get darker.
  • Skin comes out darker than with the Tri-X 400 (75.5) or HP5 Plus (73.6) weights: of all the Grain Archive black-and-white styles, this one gives blue the most weight.
• Shadows that block up. At EI 3200 the film is underexposed by about 1⅔ stops, and the tone curve drops the shadows into its toe. On one test photo, the darkest 5 % fall from L 2.6 to 0.0 and 27.3 % of the pixels end up near black (at most 5/255), against 1.7 % in the base render and 16.0 % with the Tri-X 400 style. A wall in shade goes from L 5.1 to 1.2.
• Highlights that hold. A gradual shoulder keeps the brightest 5 % at 87.1, close to the base render (87.9) and below the Tri-X style (90.6). On an overexposed portrait, only 1.5 % of the pixels reach 250/255, against 9.9 % with the Tri-X style.
• Contrast from the shadows. Overall contrast rises from 14.3 to 19.2 on one photo and from 30.7 to 32.7 on another, about as much as with the Tri-X style (18.0 and 33.5). The difference is where it comes from: the blacks, not the whites.
• Darker midtones. The sea loses 4.0 L*, the pink T-shirt 5.6 and one whole image 6.8: the darkest rendering of the black-and-white styles we compared.
• Heavy grain, everywhere. Measured on the same sky at 2560 px, the grain comes out at 11.3, against 6.7 for the Tri-X 400 style and 4.8 for the Fomapan 100 style. A low midtones bias keeps it visible in the whites and shadows.
• A truly neutral gray. Chroma falls from 8.6 to 0.0: no color cast is left.

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. The style contains two color calibration instances:

  • a disabled one with no instance name, which replaces your main color calibration and switches it off. It is set to “as shot in camera” with CAT16, like darktable’s default, so you can switch it back on;
  • the “N&B” instance, which is added and does the black-and-white conversion.

  Why: when an active color calibration runs after the black-and-white conversion, its chromatic adaptation tints the gray. We measured a blue cast of b* −4 to −8 in our renders before adding the disabled instance. darktable’s built-in black-and-white presets also bypass chromatic adaptation, and film does not white-balance either.

• It also replaces your tone curve and grain. When you apply a style from the lighttable or the darkroom, each of its modules replaces the instance of the same module with the same name, if the photo has one, and is added otherwise. The style’s tone curve and grain carry no instance name, so they replace any settings you had already made in those modules. Your earlier settings remain in the history.

• Your pipeline order. The style file carries no module order list, so it does not impose one on your image.

Exporting with a style, or rendering with darktable-cli, works differently: every module of the style is added as a separate instance, and the disabled color calibration still switches off the existing one. Our measurements were made that way, on darktable’s default rendering. The details are in Install and apply darktable styles.

Limits

• An interpretation, not a calibration. No film was scanned or measured to tune the style.
• Only the pushed look. Exposed at EI 1000 or 1600, Delta 3200 keeps its shadows and looks softer, according to The Darkroom, Blue Moon Camera and Emulsive. The style does not render that use.
• Compressed, not destroyed. The style squeezes the shadows, but part of the RAW’s shadow detail is still there in the blacks. A truly underexposed negative no longer holds that information.
• The spectral curve. It was read by eye from the chart and, like darktable, we treat the axis as log sensitivity.
• The grain. Harman publishes no granularity, so the grain was set from reviews. It aims at 35 mm: in 120 the real grain is subtler. darktable’s grain is procedural noise: it imitates the texture of film grain, not the shape of tabular crystals, and its visibility depends on the export size.
• The developer. The tone curve targets DD-X or Microphen, the developers Ilford recommends for EI 3200.

Tips

• For an EI 1600 look, soften the toe of the tone curve, for example to (0.1, 0.04) (0.2, 0.12) (0.3, 0.23). We have not tested this variant.
• For a 120 look, lower the grain strength.
• See the spectral conversion alone by switching off the style’s tone curve and grain instances.
• Back to color: switch the main color calibration back on and switch off the “N&B” instance.
• Installation: see Install and apply darktable styles.