LCH Components From LAB Converter
Convert caller same-reference CIELAB axes to polar CIELCH with [0,360) hue; neutral hue uses zero sentinel with unavailable flag, not a misleading hue assignment or RGB/OKLCH converter.
Description
CIELCH expresses CIELAB a/b axes in polar form.
When to use LCH Components From LAB Converter
Use LCH Components From LAB Converter when you need to evaluate the supplied records under the calculation and evidence rules below. No RGB or OKLCH conversion and no reference-white adaptation is performed.
Prepare colors in the stated color space and scale. Use encoded RGB fractions, linear RGB, Lab, xy, byte values or ink percentages exactly as requested; supply caller tolerances and reference conditions.
How to use LCH Components From LAB Converter and understand its results
- Prepare colors in the stated color space and scale. Use encoded RGB fractions, linear RGB, Lab, xy, byte values or ink percentages exactly as requested; supply caller tolerances and reference conditions.
- Enter labComponents using the field table and calculation rules, then run the tool.
- Read lchComponents, chromaticHueAvailable. The explanation below defines the units, signs, ordering and any flags or placeholder values.
- If the tool reports an input issue, correct the values and run it again. Apply the stated assumptions when interpreting a successfully returned result.
| Input field | Meaning | Value type; see rules below | Requirement |
|---|---|---|---|
| labComponents | Lab components | list of number | Required |
Enter three same-reference Lab values with L 0–100 and a/b bounded±200. Return L/C/h and hue-available flag; zero chroma uses hue 0 as sentinel.
C=hypot(a,b); h=atan2(b,a) normalized to0–360 Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.
| Output field | Meaning | Value type |
|---|---|---|
| lchComponents | Lch components | list of number |
| chromaticHueAvailable | Chromatic hue available | boolean |
{
"input": {
"labComponents": [
50,
3,
4
]
},
"output": {
"lchComponents": [
50,
5,
53.13010235415595
],
"chromaticHueAvailable": true
}
}Limitations and assumptions
No RGB or OKLCH conversion and no reference-white adaptation is performed.
Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Numeric lists are limited to 10,000 entries; string lists to 128 strings of at most 128 characters each. The rules above may impose smaller limits. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors. A successfully returned false flag is an evaluated outcome; its meaning is explained above.
Alternative or Complementary methods
Use Diverging Scheme Midpoint Neutral Check: A diverging scheme’s neutral midpoint can be screened by Lab chroma. Neutrality alone does not establish endpoint balance. For a complementary task, use Delta E CIE2000 Calculator: CIEDE2000 adjusts Lab color differences for lightness, chroma and hue interactions. Neutral chroma and hue wrapping require explicit handling.
Further background: CSS Color Module Level 4.
References
-
LCH Components From LAB Converter — tool.io
-
CSS Color Module Level 4 — World Wide Web Consortium
Similar or alternative tools
- Diverging Scheme Midpoint Neutral Check
A diverging scheme’s neutral midpoint can be screened by Lab chroma. Neutrality alone does not establish endpoint balance.
- Delta E CIE2000 Calculator
CIEDE2000 adjusts Lab color differences for lightness, chroma and hue interactions. Neutral chroma and hue wrapping require explicit handling.