darktable preset inspired by KodakPortra 160

What the style changes

The style contains five darktable modules. It aims at the soft, muted Portra 160 described on the Kodak Portra 160 film page: low contrast, restrained color, natural skin, neutral highlights, slightly cool shadows and very fine grain. All figures below come from renders made with darktable-cli 5.6.0 at 1000 px, measured in CIELab.

• A flatter curve than Portra 400. The tone curve raises the blacks and rounds the highlights; its midtone slope is 0.98, against 1.04 in the Portra 400 style. Contrast ends slightly below the base (Lsd 14.3 → 14.0 and 30.7 → 30.0), and the darkest 5 % of the frame rise from L 2.6 to 5.0. The gap stays small on purpose: Kodak’s datasheet shows the same slope for Portra 160 and 400, and only the reviews find the 160 softer.
• A muted palette. The “film” color balance rgb lowers chroma by 8 %. Sky chroma drops by 20 % (27.5 → 22.0), sea by 19 %, the pink T-shirt by 15 % and orange vests by 21 % (37.8 → 30.0). The color equalizer then raises oranges, so skin loses only 5 % of its chroma (16.4 → 15.5) instead of 13 %.
• Slightly warm skin, neutral highlights. Skin hue moves from 44.2° to 48.4°. A white wall stays neutral (C 0.8 → 0.7), where the Portra 400 style warms it (C 2.7).
• Cooler shadows than the Portra 400 style. The shadow tint is strong (0.03) because the raised blacks desaturate the shadows. On a ground shadow, a*/b* read 0.0/−0.9, against 1.7/0.2 with the Portra 400 style.
• Sky hue kept. The sky stays at about 272°, as with t3mujinpack, while the Portra 400 style pushes it toward violet (278.7°). This is the most visible difference between the two styles.
• Very fine grain, sized from Kodak’s Print Grain Index of 28. On the sky of photo 0775 exported at 2560 px, high-frequency noise measures 1.77 (8-bit levels), against 2.86 with the Portra 400 style: 38 % less, in line with PGI 28 against 37.

For comparison, the t3mujinpack Portra 160 style lightens the image and saturates skin (+15 %) and the pink T-shirt (+23 %). This style follows the muted palette the reviews describe.

What it leaves alone

• Your base development. The style contains no exposure, no sigmoid or filmic, no white balance, no color calibration and no LUT, so those settings stay as you set them.
• Your color balance rgb. The style’s instance is named “film”, so it is added next to the color balance rgb you tuned on the photo instead of replacing it.
• Your pipeline order. The style file carries no module order list, so it does not impose one on your image.
• But not your settings in its other modules. When you apply the style from the lighttable or the darkroom, darktable 5.6 replaces an existing instance of the same module: if you had already adjusted rgb primaries, color equalizer, tone curve or grain, the style’s settings take their place. Your earlier settings stay in the history stack. Applying the style at export, or with darktable-cli as in our measurements, adds every module as a separate instance instead. See Install and apply darktable styles for the details.

Limits

• An interpretation, not a calibration. The style is built from Kodak’s datasheet and published reviews. No film was scanned or measured to tune it.
• Contrast. The lower contrast comes from the reviews, not from the datasheet, and some reviews disagree. The style keeps the difference small.
• Overexposure. Real Portra 160 turns cyan beyond about 1.5 stops of overexposure, and its red layer flattens above about 3.5 stops over middle gray. The style does not simulate either: darktable’s rgb curve, which could bend each channel separately, works on linear values before sigmoid, so there is no reliable point to place that threshold.
• Sea hue. The cool shadow tint also pushes the sea toward cyan (h 270.1° → 263.3°). t3mujinpack goes the same way (266.5°), but no source describes it.
• Curve readings. The datasheet curves were read from the digitized graph: they are orders of magnitude, not measurements.
• Subtle by design. On some images, the difference from darktable’s default rendering lies mostly in vivid colors and grain. The grain depends on export size: at 1000 px, it is barely visible.

Tips

• For a lighter, softer look, overexpose slightly with the exposure module. The style will not add the cyan shift real Portra 160 shows when heavily overexposed.
• Adjust skin without touching the rest in the style’s color equalizer instance: its orange saturation sets how much color skin keeps.
• Compare with the Portra 400 style on two duplicates of the same photo: the 160 is flatter, more muted, with a neutral sky.
• Installation: see Install and apply darktable styles.