Primera Suite

Primera is my personal suite of DaVinci Resolve Studio color grading DCTLs for both clip-level grading and some aspects of look development. The DCTLs are built via reusable code fragments via make (+ plenty of help from Claude). The latest release of the built DCTLs is always available in the sidebar to the right as a .zip file —>

Most of the underlying math comes from tried-and-tested publicly-available imaging science approaches and from my own extensive use of open-source DCTLs by many generous members of the “color-concerned community" (see at bottom). Primera consolidates the approaches I reach for most often into one place, under one name, and with only the controls I actually use.

My personal aesthetic lodestar is still a "film look," in the broad sense, but rather than emulating any specific stock or process (with one exception), I’m more chasing my personal past and on-going "sense memories" of seeing and working with film. But hopefully the tools are flexible enough to achieve most any look/style.

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, and Fuji F-Log2

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)

• 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 — Scales output to a nominal level before density adjustment. Runs before Cinecolor (see below)
• Soft Clamp — tanh in the shoulder + exponential compression in the toe after interpolation to softly limit range excursion
• Hard Clamp — Clips to [0,1] before interpolation; both clamping 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
• 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). Targets a "fuzzy pie slice" of the HSV disc centered on the nominal skin tone hue angle (~28°) and applies adjustments within that region. Everything outside the mask passes through untouched.

• 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)
• Evenness — Compresses hues toward the skin center; meant to emulate HMU evening-out talent skintones on set during shooting
• 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 — Three-zone false-color overlay showing skin qualification: gold = in zone, red = hue too far clockwise, cyan = hue too far counter-clockwise
• Legend — displays color-coded blocks corresponding to each false color zone; 'Gr' (green) = hue too far counterclockwise; 'Sk' (gold) = in the skin zone; 'Rm' (red-magenta) = hue too far clockwise

Gamut containment is done via the same "soft squeeze" described above (tanh in the shoulder/exponential compression in the toe). I don't use this on every shot but it can be handy for "surgical" chroma operations targeting skintones without resorting to spatial tools.

Notes

• For the curious, the math used in the Primera tools is available in both typst and PDF (feedback welcome)
• Maybe/hopefully it goes without saying, at this point, but the Primera tools are meant to be used in the context of a fully color-managed workflow. See here for a decent primer.
• The Primera tools should play nicely with most any DRT (DRT = Display Rendering Transform, the final image formulation stage prior to outputting a deliverable) but has been used/tested most with my preferred DRT, Jed Smith's OpenDRT
• I also regularly use/test the tools with Resolve's CST, Juan-Pablo Zambrano's excellent 2499 DRT, the ACES 2.0 transforms, and occasionally a favorite LUT
• Note that it is possible to produce negative or otherwise out-of-range values with these tools, despite the guardrails in place. If this happens, I'd reach for gamut compression first to wrangle things back into range. If something’s really broken though, please file an issue.
• Kaur Hendriksen made a great, free standalone DCTL that implements the ACES 2.0 gamut compression coefficients which I can whole-heartedly recommend (Resolve's ACES Transform or Color Space Transform could also be used)

Inspiration

There's not much particularly original in the Primera tools, like I said they're more of a curated/opinionated collection of my favorite approaches to primary grading and some aspects of look development. In no particular order, Primera owes 90%+ of its existence to the work of the following individuals:

• Jed Smith
• Juan Pablo Zambrano
• Moaz Elgabry
• Thatcher Freeman
• Paul Dore
• Kaur Hendrikson
• Calvin Silly / hotgluebanjo