Monochrome Lightness Steps Generator

Generate endpoint-inclusive bounded HSL lightness ladder retaining caller hue/saturation and allowing descending ramps; not perceptually uniform OKLCH steps or a guarantee of distinguishable colors.

Description

An HSL monochrome ramp keeps hue and saturation fixed while varying lightness.

An HSL monochrome ramp keeps hue and saturation fixed while varying lightness. Endpoint order may ascend or descend.^[1]

Enter hue bounded±10^9 degrees, saturation/start/end fractions 0–1 and integer steps 2–128. Normalize hue and return endpoint-inclusive lightness/RGB rows.

When to use Monochrome Lightness Steps Generator

Use Monochrome Lightness Steps Generator when you need to evaluate the supplied records under the calculation and evidence rules below. No uniform perceptual spacing or distinguishability guarantee is supplied.

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 Monochrome Lightness Steps Generator 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 hueDegrees, saturationFraction, lightnessStartFraction, lightnessEndFraction, stepCount using the field table and calculation rules, then run the tool.
Read lightnessFractions, rgbStepRows. 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
hueDegrees	Hue degrees	number	Required
saturationFraction	Saturation fraction	number	Required
lightnessStartFraction	Lightness start fraction	number	Required
lightnessEndFraction	Lightness end fraction	number	Required
stepCount	Step count	number	Required

Enter hue bounded±10^9 degrees, saturation/start/end fractions 0–1 and integer steps 2–128. Normalize hue and return endpoint-inclusive lightness/RGB rows.

lightness_i=start+(end−start)×i/(steps−1)

Units, indexing, boundary conditions and exceptional cases are defined in the calculation rules above.

Output field	Meaning	Value type
lightnessFractions	Lightness fractions	list of number
rgbStepRows	Rgb step rows	list of list of number

json

{
  "input": {
    "hueDegrees": 0,
    "saturationFraction": 1,
    "lightnessStartFraction": 0,
    "lightnessEndFraction": 1,
    "stepCount": 3
  },
  "output": {
    "lightnessFractions": [
      0,
      0.5,
      1
    ],
    "rgbStepRows": [
      [
        0,
        0,
        0
      ],
      [
        1,
        0,
        0
      ],
      [
        1,
        1,
        1
      ]
    ]
  }
}

Limitations and assumptions

No uniform perceptual spacing or distinguishability guarantee is supplied.

Numeric inputs, where present, must be finite. Follow the calculation-specific rules for overflow, underflow and exceptional cases. Missing required fields, extra fields, wrong value types and violations of the calculation rules are input errors.

Alternative or Complementary methods

Use Color Shade and Tint Generator: Tint and shade ladders mix toward white and black respectively. The declared method operates on encoded sRGB. For a complementary task, use HSL Lightness Shift Percent: An additive HSL lightness shift uses percentage points rather than a brightness multiplier. Clipped values retain the source hue/saturation.

References

Monochrome Lightness Steps Generator — tool.io

Similar or alternative tools

Color Shade and Tint Generator
Tint and shade ladders mix toward white and black respectively. The declared method operates on encoded sRGB.
HSL Lightness Shift Percent
An additive HSL lightness shift uses percentage points rather than a brightness multiplier. Clipped values retain the source hue/saturation.