Methodology
Hue Codex is primarily a browser color tool. Its gamut and print guidance is useful for screening and handoff notes, but it is not a replacement for ICC profiles, proofs, calibrated devices, or vendor specifications.
Hue Codex treats HEX input as an sRGB source. It can describe how that source fits inside wider display spaces and can calculate approximate CMYK values, but it does not perform press-ready profile conversion.
These badges identify which parts of this methodology are standards-backed, draft-track, Hue Codex-specific, approximate, or dependent on browser behavior.
This separates standards-based formulas from Hue Codex implementation decisions, product heuristics, and known limitations for this methodology.
Formula, threshold, syntax, or data behavior taken from a cited standard or standards-backed source.
How Hue Codex chooses to parse, normalize, round, export, or sequence calculations.
Product rankings, bands, labels, suggestions, or role hints that are useful guidance but not external standards.
Caveats, edge cases, browser dependencies, approximations, or contexts the method does not prove.
Hue Codex normalizes ordinary tool input to sRGB HEX. For a HEX source, the gamut checker reports sRGB as in gamut, wider RGB display spaces as containing the color, and the browser fallback as the same HEX value.
This is intentionally conservative: the site can know the numeric color you entered, but it cannot know the display profile, printer profile, substrate, ink set, viewing booth, or brand production tolerances.
CSS Color 4 defines modern color syntax for device-independent values and predefined color spaces. Hue Codex surfaces these formats when they are useful for CSS handoff and explains when fallbacks should be kept.
When a color is converted back to sRGB for display or copying, channel values are clamped to the displayable range. A clipped fallback can be usable, but it is not a perceptual gamut-mapping strategy.
Hue Codex calculates simple CMYK-like values from sRGB channels by deriving black from the maximum RGB component, then deriving cyan, magenta, and yellow from the remaining distance. This is useful for rough language only.
CSS Color 5 device-cmyk() is draft-standard context, not a promise of press-ready color management or final specification status.
Real print conversion depends on ICC profiles, total ink limits, black generation, paper, ink, press condition, and vendor setup. Always use proofing and production guidance for final print values.
| Input | Expected behavior |
|---|---|
| Any normalized HEX | Reported as an sRGB source |
| #000000 | Approximate CMYK black channel reaches 100 percent |
| An sRGB source in Display P3 notes | Reported as contained, not magically wider than sRGB |
| CMYK export | Warned as approximate and not press-ready |
Hue Codex CMYK output is a deterministic sRGB approximation for communication. It is not a profile-aware conversion.
rgb_to_cmyk_approx(r8, g8, b8):
r = r8 / 255
g = g8 / 255
b = b8 / 255
k = 1 - max(r, g, b)
if k >= 1:
return c = 0, m = 0, y = 0, k = 100
c = ((1 - r - k) / (1 - k)) * 100
m = ((1 - g - k) / (1 - k)) * 100
y = ((1 - b - k) / (1 - k)) * 100
k = k * 100
return c, m, y, kThese vectors validate the simple sRGB-derived CMYK approximation. They are not ICC profile conversions or press targets.
| Input | Expected output | Notes |
|---|---|---|
| #000000 | cmyk(0% 0% 0% 100%) | Black channel reaches 100 percent |
| #FFFFFF | cmyk(0% 0% 0% 0%) | No ink in the simple approximation |
| #00FFFF | cmyk(100% 0% 0% 0%) | Pure sRGB cyan maps to cyan only |
| #FF0000 | cmyk(0% 100% 100% 0%) | Pure sRGB red maps to magenta and yellow |
| #4169E1 | raw c=71.111111%, m=53.333333%, y=0%, k=11.764706%; displayed cmyk(71% 53% 0% 12%) | Rough communication value only |
These references anchor the public standards and formats used by Hue Codex. Status badges distinguish stable standards, drafts, Hue Codex heuristics, approximations, and browser-dependent behavior.
These Hue Codex tools link to this methodology because they depend on the formulas, assumptions, limits, or data policy described here.