Primera Suite

Primera

Primera.dctl is the foundation and provides primary grading controls for shot-to-shot balancing:

• Exposure — Linear gain in photographic stops (2^n) applied before the selected transfer function
• Black Point — Smooth compression of the darkest tones approaching black (sometimes called "flare," e.g. in Baselight)
• Temp / Tint — self-explanatory ("white balance"); operates in linear space
• Contrast — a typical Log-space stretch/squash of the tonal range around a variable Pivot which defaults to the transfer function's mid-grey point
• Shadows / Highlights — Linear gain constrained below/above mid-grey; no spatial operations so can be encoded in a 3D LUT
• Roll Off — tanh highlight compression controlling where the brightest values top out; works with Highlights to shape/compress the shoulder
• Neg. Saturation — Multiplicative negative RGB gain on chroma (only darkens)
• Pos. Saturation — HSV-based saturation boost (gain on the 'S' "channel"), positive only; adds "density"
• Preserve Luma — weighted offset of the darkening effect from both saturation controls
• Show Chart — draws a per-transfer-function step chart graduated in stops a la Walter Volpatto's example
• Transfer Function — for now, only the ones I encounter most in my day-to-day: LogC3, LogC4, REDLog3G10, S-Log3, ACEScct, DaVinci Intermediate, Kodak Cineon, Fuji F-Log2, and Panasonic V-Log

Primera Hue

PrimeraHue.dctl performs per-channel hue and density control via tetrahedral interpolation, based on hotgluebanjo’s DCTL implementation of the approach described by Steve Yedlin ASC in his DisplayPrep demo (2018). This tool expects a log source (not scene-linear).

• 6 Hue sliders (R/Y/G/C/B/M) — Each pushes a color toward/away from its neighbors via Rodrigues rotation around each corner's achromatic axis. +/-60° per channel covers the full 360°
• 6 Density sliders — Makes the shifted color subjectively more "colorful" without adding energy
• Preserve Luma — Restores pre-adjustment Rec. 709 luminance by uniform gain. Runs after the hue/density interpolation and before Cinecolor (see below)
• Soft 🗜️ (soft squeeze, on by default) — tanh in the shoulder + exponential compression in the toe, applied last, to softly limit range excursion
• Hard 🗜️ (hard squeeze) — Clips the rotated corner values to [0,1] before interpolation, not the pixel itself; both squeeze schemes can be applied at the same time ("all the clamps")
• Cinecolor — emulates a budget color process (~late '30s-early '50s), similar to Technicolor Process 2, that used bipacked (contact exposure) ortho negatives and duplitized print stock (emulsion on both sides of the base); here for you now in the 2020s without the registration nightmares
• Protect Skintones — Applies only to Cinecolor. Creates a holdout matte centered on the skintone indicator (~28° on an HSV disc) with smooth falloff

Primera Split

PrimeraSplit.dctl provides subtractive color split-toning for imbuing shadows and highlights with (usually) contrasting color casts. Lately conceptualized less as an ‘effect' and more a fundamental look development tool, defining the chroma dimensions of the characteristic curve.

• Mid-Grey Pivot — Defaults to the selected transfer function's mid-grey (but should be set purely by eye)
• Transition Softness — self-explanatory
• Preserve Luminance — as in Primera and PrimeraHue
• Show Ramp — overlays a greyscale ramp put through the identical toning pipeline, so you can read the tint applied at every tonal position
• Ramp Position — positions the greyscale ramp vertically (useful when blanking has been applied)
• Show Curve — shows an RGB curves representation of the the current slider states
• Show Pivot — visualizes the position of the pivot point and transition softness
• Show Chart — draws a per-transfer-function step chart graduated in stops a la Walter Volpatto's example; prints the curve name and 18% grey value over a rectangle of the same value
• Transfer Function — Aligns Pivot to the appropriate mid-grey point

Primera Skin

PrimeraSkin.dctl is a dedicated skintone sculpting tool operating in HSV. Meant for log-based timelines (any camera's log or log/log-like working spaces like DaVinci Wide Gamut/Intermediate or ACEScct). Everything outside the mask passes through untouched. I don't use this on every shot but it can be handy for "surgical" chroma operations targeting skintones. It mostly does what you might want but is still an on-going work-in-progress. One slider (Soften) performs a spatial operation so the node this tool is on should be bypassed when creating a 3D LUT.

Detection is rg-chromaticity-based rather than a plain hue/saturation slice: the pixel is normalized by r+g+b, which makes the ratios invariant to overall brightness, so the mask should catch fair and dark skin equally well. Log-space skin clusters tightly around g/(r+g+b) ≈ 0.33 with red leading blue. A hue gate centered on the nominal skin angle (~28°) attempts to keep Range meaningful as a user control. In other words, it creates a "fuzzy pie slice," centered on the skintone line with a chromaticity gate in front of it.

• Hue — Rotates skin hue (+/-20°)
• Saturation — Scales HSV saturation within the mask (gain on the 'S' "channel")
• Density — Adjusts value/brightness (positive = darker)
• Range — Widens or narrows the skin mask (0.25 = tight, 2.0 = broad)
• Soften — Spatial pooling of the mask. Soften pools the mask over a sparse 37-tap neighborhood (weighted by distance and chroma similarity) and soft-unions the result with the pixel's own mask, so it can only fill holes, never erode a confident edge. Radius is resolution-independent (~15px at UHD at full strength). At 0 no taps are made at all. Note that spatial operations cannot be represented in a 3D LUT.
• Evenness — Compresses hues toward the skin center; meant to emulate HMU evening-out talent skintones on set during shooting
• Separation — This control Inverts the (pooled) skin mask, acting on everything that isn't skin. The inverted mask gates a gentle hue migration toward the band opposite the skin vector — skin sits at 28°, its complement at ~208°, the cyan/teal band. This is the mechanism underlying, conceptually, the teal-and-orange look: complementary opposition between a warm subject and a comparatively cool field. This control attempts to keep neutrals, well, neutral and is capped at ~30% migration (27° max). Pay special attention to reds however, crimson drifts toward magenta well before the slider runs out of travel.
• Low Gate / High Gate — Value-based gates that exclude dark or bright pixels from the mask (useful for protecting shadows and specular highlights)
• Show Mask — False-color overlay of mask qualification. Gold = in the skin zone; green/cyan = hue sits counter-clockwise of skin center; magenta = hue sits clockwise of it. Tint intensity tracks mask strength. Zone classification uses the original hue, and so tries to stay stable as the Hue slider is moved
• Legend — A continuous gradient strip across the bottom 7.5% of frame, labeled GREEN / SKIN / MAG. left to right, matching both the Show Mask colors and the Hue slider's direction (left = green, right = magenta).

Gamut containment is done via the same "soft squeeze" described above (tanh in the shoulder and exponential compression in the toe), but here it is scaled by the mask. Pixels that are only faintly pooled into the mask get proportionally less clamping squeeze to avoid the (spatial) Soften control introducing banding around faces against bright or dark backgrounds.