Color science reference

Regarding Colorimetry: comprehensive outline

Complete outline of the colorimetry series.


Module 1: The Hardware of Sight

Physics & Psychophysics

  • Spectral Power Distribution (SPD)
    • Continuous vs discontinuous spectra
    • Metamerism failure
  • Color Rendering Index (CRI)
    • R1-R8 limitations
    • Critical values: R9, R13, R15

Photoreceptors

  • Cones (Photopic vision)
    • L, M, S cone types
    • Opponent processing
  • Rods (Scotopic vision)
    • Purkinje effect

Perception Anomalies

  • Helmholtz-Kohlrausch effect
  • Abney effect
  • Bezold-Brücke shift
  • Weber-Fechner Law

Integration Formula

  • Color as spectral integration
  • SPD × Reflectance × Observer sensitivity

Module 2: Measuring Color

Historical Development

  • Wright-Guild experiments
  • Color-matching functions

CIE 1931 XYZ System

  • XYZ tristimulus values
  • Chromaticity coordinates (x, y)
  • Chromaticity diagram (“horseshoe”)

Perceptual Non-Uniformity

  • MacAdam ellipses
  • Just Noticeable Difference (JND)

Lab* Color Space

  • L* (Lightness)
  • a* (Red-Green axis)
  • b* (Blue-Yellow axis)
  • ΔE color difference metric

Analog Legacy

  • Hurter-Driffield (H-D) curve
  • Film response characteristics
  • Digital log curves

Module 3: The Digital Image Pipeline

Scene-Referred vs Display-Referred

  • Scene-referred: Linear, unbounded
  • Display-referred: Non-linear, bounded

Transfer Functions

  • Gamma 2.2
  • sRGB (piecewise)
  • LogC3 (ARRI)
  • ST.2084 PQ (HDR)

Color Models

  • RGB (device-dependent, additive)
  • YCbCr (luminance + chroma)
  • HSL (perceptually broken)
  • Lab* (perceptually uniform)
  • ICtCp (HDR-optimized)

Tone Mapping & View Transforms

  • Contrast compression
  • Gamut mapping
  • Output transforms

Module 4: ACES & Modern Color Management

ACES Architecture

  • IDT (Input Device Transform)
  • AP0 (ACES 2065-1) - Archive space
  • AP1 (ACEScg) - Working space
  • ODT (Output Device Transform)

AP0 Primaries

  • Imaginary primaries
  • Future-proof gamut

AP1 Primaries

  • Real primaries
  • Grading/rendering space

Gamut Problems

  • Blue light artifacts
  • Negative RGB values
  • Gamut compression solutions
  • ACES 2.0 improvements

Practical Workflows

  • Save in AP0, work in AP1
  • Camera IDTs
  • Display ODTs

Module 5: The Display Ecosystem

HDR Standards

  • PQ (ST.2084) - Absolute luminance
  • HLG (ARIB STD-B67) - Relative luminance

Viewing Environment

  • Bartleson-Breneman effect
  • Theatrical, home, office standards
  • Surround luminance impact

System Color Management

  • NCLC tags
  • QuickTime gamma shift
  • Apple EDR
  • Platform-specific handling

Module 6: Camera Architectures & Case Studies

ARRI

  • LogC3 (14 stops, Middle Grey = 39%)
  • LogC4 (17 stops, Middle Grey = 32%)
  • K1S1 Transform
  • Wide Gamut 3

RED IPP2

  • Log3G10 (13 stops)
  • REDWideGamutRGB
  • Philosophy: “Maximum data, colorist decides”

Sony Venice

  • X-OCN format
  • S-Gamut3.Cine
  • Hybrid approach

RAW Mechanics

  • Bayer pattern (RGGB)
  • Demosaicing algorithms
  • dcraw open-source decoder

Module 7: Computational Color & Advanced DIT

Advanced Color Matching

  • 3×3 matrix transforms
  • Thin-Plate Splines (TPS)

LUT Mathematics

  • 33×33×33 cube structure
  • Trilinear vs tetrahedral interpolation
  • Inverse LUT problems

Security & Algorithms

  • Visual encryption
  • RSA metadata
  • DCTL shaders
  • True security (AES-256 + DRM)

Conclusion

Color science is the intersection of:

  • Biology - LMS cones, opponent processing, logarithmic perception
  • Physics - SPD, reflectance, integration
  • Mathematics - Matrices, transforms, perceptual quantization
  • Engineering - Sensors, codecs, display calibration
  • Craftsmanship - Translating DoP’s vision into audience experience

The DIT’s Role: Translator between emotion and data, between sensor and screen.