SCIENCE DES COULEURS
LUTs as Parametric EQs
MODULE · LUTS AS EQ A lookup table is a translation list. Audio engineers already own the best metaphor: fixed-band EQ for 1D LUTs, fully parametric EQ for 3D LUTs—center, width, and gain, but for colors instead of frequencies.
Parametric EQ · audio Logic / Pro Tools style · drag to edit
3D LUT · color RGB lattice · drag to orbit · auto-rotate
R G B node = band · ring ≈ Q · arrow ≈ gain
AUDIO ↔ COLOR
Audio Color
EN PROFONDEUR
What a LUT is (without the mystique)+
A lookup table stores answers in advance. For color, the question is: “If the input is this RGB (or this code), what RGB should I output?” A 1D LUT answers with three independent curves. A 3D LUT answers with a 3D lattice of RGB→RGB samples and interpolates between them. Nothing magical—just memory and math standing in for a function you could not run as a closed formula in real time, or that is easier to measure than to invent.
1D LUT ≈ fixed-band / graphic EQ+
A graphic EQ gives you fixed frequency slots; each slider only moves its band. A 1D LUT is three graphic EQs for R, G, and B: each channel is reshaped alone. That is perfect for global tone—gamma, contrast S-curves, white-balance-ish channel gains, monitor greyscale. It is the wrong tool when channels must talk: you cannot cleanly say “desaturate only the teal” with three independent curves. In a LUT box, 1D stages often sit as shapers before and after a 3D cube—like shelves around a parametric mid rack.
3D LUT ≈ parametric EQ (for every color)+
A parametric EQ lets you pick the center frequency, set Q (how wide), and boost or cut. A 3D LUT node is that idea on a grid of colors: the node is the “frequency” (which color), tetrahedral (or trilinear) interpolation is the “Q” (how the move blends), and the vector from input to output is the “gain.” A 33×33×33 cube is a ridiculous number of bands—enough to fix a green cast only in the midtones, or to map Rec.709 into a P3 container without a single global matrix. Brightness and contrast knobs are bass/treble. The cube is the full parametric rack.
A short history of the color LUT+
No single inventor. Print (1970s): scanner RGB→CMYK tables; tetrahedral interpolation patents (e.g. Sakamoto) still underwrite how cubes are evaluated. Computer graphics (1970s): framebuffer color maps and palette LUTs—ancestors of every GPU 1D gamma ramp. Film DI (1990s–2000s): Cineon log scans and print-film preview; FilmLight Truelight (2002) made measured lab chains into 3D cubes so a monitor could stand in for the print. Modern grading, broadcast legalizers, and display calibration inherited all three lines. (Deeper lattice anatomy lives in Anatomy of a LUT.)
Conversion vs correction vs look+
Conversion LUT: change space or transfer (log→Rec.709, 709→2020, SDR↔HDR). Correction LUT: invert a measured display’s error toward a target (the calibration cube Calman writes). Look LUT: freeze a creative grade. All three are the same machine—tables—with different authorship and trust. Pipeline order matters: a look built for Rec.709 will lie on LogC, just as an EQ preset for vocals lies on a kick drum bus.
Why shapers exist (EQ preamp analogy)+
If you dump scene-linear light into a uniform 3D lattice, the first node step can span many stops of shadow. The interpolator starves where the eye is picky. A 1D shaper bends the input into a more even domain (often log) before the 3D cube—like hitting a parametric rack at a sensible level. Serious boxes expose 1D→3D→1D for exactly this reason.
Why Red Rock OPS talks this way+
Live events, XR, and switchers (including Analog Way LivePremier dual 3D LUT slots) are full of people who already trust parametric EQ. Mapping LUTs onto that language shortens the sales and training gap: you are not installing mystery; you are installing surgical color EQ that runs in real time on every path. Measure with a probe, generate the cube, load the slot—same seriousness as tuning a room.
IF IT ISN'T MEASURED, IT ISN'T CALIBRATED. · ← LUT ANATOMY · ANALOG WAY →