darktable preset inspired by KodakPortra 800

What the style changes

The style contains five darktable modules. It aims at the Portra 800 described on the Kodak Portra 800 film page: warmer and more saturated than Portra 400, with vivid reds and yellows, no highlight shoulder and more visible grain. All figures below come from renders made with darktable-cli 5.6.0 at 1000 px, measured in CIELab.

• Slightly more contrast than the Portra 400 style. The tone curve has no shoulder, as on the datasheet, barely lifts the blacks and firms up the midtones a little. Contrast rises by 1.5 (Lsd 14.3 → 15.8 and 30.7 → 32.2), against 0.4 to 0.6 for the Portra 400 style, and the blacks hardly move (L5 2.6 → 3.0, against 4.2 for the 400).
• Warmer, richer skin. The “film” color balance rgb adds a slightly yellow warmth, mostly in the highlights. Skin hue moves from 44° to 52° and its chroma rises by 38 %. That is between the Portra 400 style (48°, +6 %) and the Gold 200 style (57°, +57 %). t3mujinpack goes the same way, further (57°, +49 %).
• Vivid reds that stay red. The color equalizer raises red and yellow saturation. The pink T-shirt gains 20 % of chroma and turns only 11° toward orange, against 19° with the Gold 200 style.
• Saturation across the range. Sky and sea keep their chroma (27.5 → 28.0 and 22.2 → 22.0), where the Portra 400 style lowers it by about 18 %. The color equalizer raises blues slightly to compensate for the warm tint.
• Discreet green shadows. A light blue-green shadow tint makes the deepest shadows (L below 15) a little less magenta: a* −1.0 to −1.3 on photos 0989, 1013 and 1014. The sea leans slightly toward cyan (h −4°).
• More grain. Sized from Kodak’s Print Grain Index of 48. On the sky of photo 0775 exported at 2560 px, high-frequency noise measures 4.8, against 2.9 for the Portra 400 style and 4.3 for the Gold 200 style: the same order as the PGI.

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 is a debatable choice. The datasheet and part of the reviews show no more contrast than Portra 400. The style follows the reviews that see a little more, and keeps the difference moderate.
• Green shadows. According to the reviews, they come with underexposure. The style applies a fixed, light tint: it cannot reproduce how the film responds to exposure.
• Skin. Sources disagree: warmer than Portra 400 for most, more accurate for one. The style follows the majority.
• Not simulated: the glow around light sources that one lab describes, and the look of push processing.
• The grain depends on export size: at 1000 px, it is barely visible.

Tips

• On dark, low-light frames, the green shadow tint shows more. Lower the shadows chroma of the “film” color balance rgb if it gets in the way.
• To suggest a pushed roll, raise the strength of the style’s grain instance. Real push processing also changes contrast and shadow detail, which the style does not model.
• Everything stays editable. Each module the style adds is an ordinary instance: you can adjust it or switch it off afterwards, for example the “film” color balance rgb if skin looks too warm.
• Installation: see Install and apply darktable styles.