Method scope
CPS is a deterministic, first-party digital reference system. Each core record contains a stable code, public name, family, tone, intensity, HEX, RGB, CMYK approximation, OKLCH, CIE Lab, contrast measurements, print-planning fields, and use metadata.
Reference generation in OKLCH
Each chromatic family has a registered hue and maximum chroma. Eleven fixed tone lightness targets are combined with four intensity multipliers: Soft, Balanced, Vivid, and Electric.
A lightness-dependent taper reduces chroma toward the lightest and darkest ends of a family. This prevents very pale or very dark tones from being assigned unrealistic chroma values. Neutral families use a dedicated low-chroma profile and the N intensity code.
The resulting OKLCH color is converted into an sRGB HEX value for browser display and downstream calculations.
Digital color conversions
RGB values are derived from the final sRGB HEX reference. CIE Lab and OKLCH fields are calculated from that final displayed value, so matching and published coordinates correspond to the color users actually see in a compatible browser.
CMYK values use a generic mathematical conversion from sRGB. They are included for early planning, not device-specific production.
Unique HEX enforcement
The generator checks whether an sRGB HEX value has already been assigned. When gamut conversion produces a duplicate, it applies a small, bounded chroma and hue adjustment until a unique display value is found.
Nearest-reference matching
Input colors are converted to CIE Lab, then compared with CPS records using the CIEDE2000 color-difference formula. Results are sorted from the lowest ΔE00 value to the highest.
A lower ΔE00 means a closer mathematical relationship within the available digital data. It does not prove that two printed materials, displays, paints, textiles, or inks will look identical.
Primary formula reference: Sharma, Wu, and Dalal, “The CIEDE2000 Color-Difference Formula.”
Accessibility fields
Each CPS reference stores contrast against white and near-black text candidates. The preferred text field chooses whichever candidate produces the higher calculated ratio.
The benchmark report applies WCAG contrast thresholds to opaque sRGB pairs. These fields do not inspect font size, weight, opacity, images, interaction states, focus visibility, or surrounding components.
Primary guidance: W3C Understanding Success Criterion 1.4.3: Contrast (Minimum).
Print-planning fields
Total ink is the sum of the generic C, M, Y, and K percentages. Color Pick labels values over 220% as Medium risk and values over 280% as High risk for early planning.
These thresholds are internal planning heuristics. Production decisions require the printer’s ICC profile, press conditions, substrate, coating, proof, and approved specification.
Release validation
A public CPS release must pass automated checks for:
- expected family, tone, intensity, collection, and total-record counts;
- unique canonical codes and unique HEX values;
- valid numeric code structure and public display format;
- valid HEX, RGB, CMYK, OKLCH, Lab, contrast, and print fields;
- working aliases for supported legacy codes;
- successful TypeScript, lint, static build, and route tests.
Known limitations
- sRGB output is constrained by browser color rendering and device calibration.
- Mathematical color distance does not capture every material or viewing condition.
- Contrast compliance is pair-specific and is not a complete accessibility certification.
- CMYK values are generic planning approximations, not physical spot-color formulas.
- Names and recommended uses are organizational metadata, not scientific classifications.