Contrast Amplification
Text rendered light-on-dark (negative polarity) requires roughly 10% higher luminance contrast and one weight step heavier than the same text dark-on-light to achieve perceptual parity, because of halation: bright glyphs…
$ aoe install @community/fact-contrast-amplificationProjection
Always in _index.xml · the agent never has to ask for this.
ContrastAmplification [fact] v1.0.0
Light-on-dark text (negative polarity) needs ~10% higher contrast and slightly heavier weight than dark-on-light to feel equally legible, because halation around bright glyphs on dark backgrounds reduces effective edge sharpness.
Text rendered light-on-dark (negative polarity) requires roughly 10% higher luminance contrast and one weight step heavier than the same text dark-on-light to achieve perceptual parity, because of halation: bright glyphs on dark backgrounds bleed photons into adjacent dark pixels, softening edges and reducing effective contrast.
Loaded when retrieval picks the atom as adjacent / supporting.
ContrastAmplification [fact] v1.0.0
Light-on-dark text (negative polarity) needs ~10% higher contrast and slightly heavier weight than dark-on-light to feel equally legible, because halation around bright glyphs on dark backgrounds reduces effective edge sharpness.
Text rendered light-on-dark (negative polarity) requires roughly 10% higher luminance contrast and one weight step heavier than the same text dark-on-light to achieve perceptual parity, because of halation: bright glyphs on dark backgrounds bleed photons into adjacent dark pixels, softening edges and reducing effective contrast.
Meta
- License: Apache-2.0
- License Provenance: package-authorship-claim
Confidence
strong
Applies To
- dark-mode token derivation (don't naive-invert)
- weight selection: bump body weight from 400 → 450/500 in dark themes
- OKLCH lightness tuning when mirroring light tokens to dark
- checking that AA-passing light tokens still pass when inverted
Quantitative
- Contrast Amplification Factor: ≈ 1.1× (10%)
- Weight Amplification: +50 weight units typical (e.g., 400 → 450)
- Halation Mechanism: subpixel rendering + LCD photon scatter on adjacent dark pixels
Counter Conditions
- OLED displays with true blacks reduce halation considerably — amplification factor closer to 1.0.
- Astigmatism users report inverse polarity preference — halation is more pronounced for them, but the discomfort flips relative to the median user.
- Variable-font weight axes let dark-mode amplification be a continuous tweak rather than a discrete weight step.
Loaded when retrieval picks the atom as a focal / direct hit.
ContrastAmplification [fact] v1.0.0
Light-on-dark text (negative polarity) needs ~10% higher contrast and slightly heavier weight than dark-on-light to feel equally legible, because halation around bright glyphs on dark backgrounds reduces effective edge sharpness.
Text rendered light-on-dark (negative polarity) requires roughly 10% higher luminance contrast and one weight step heavier than the same text dark-on-light to achieve perceptual parity, because of halation: bright glyphs on dark backgrounds bleed photons into adjacent dark pixels, softening edges and reducing effective contrast.
Meta
- License: Apache-2.0
- License Provenance: package-authorship-claim
Confidence
strong
Applies To
- dark-mode token derivation (don't naive-invert)
- weight selection: bump body weight from 400 → 450/500 in dark themes
- OKLCH lightness tuning when mirroring light tokens to dark
- checking that AA-passing light tokens still pass when inverted
Quantitative
- Contrast Amplification Factor: ≈ 1.1× (10%)
- Weight Amplification: +50 weight units typical (e.g., 400 → 450)
- Halation Mechanism: subpixel rendering + LCD photon scatter on adjacent dark pixels
Counter Conditions
- OLED displays with true blacks reduce halation considerably — amplification factor closer to 1.0.
- Astigmatism users report inverse polarity preference — halation is more pronounced for them, but the discomfort flips relative to the median user.
- Variable-font weight axes let dark-mode amplification be a continuous tweak rather than a discrete weight step.
Sources
Relations
related: [@community/fact-light-vs-dark-default, @community/fact-line-height-readability, @community/check-color-dark-mode-cascade]
Meta
- License: Apache-2.0
- License Provenance: package-authorship-claim
Confidence
strong
Source
- Buchner & Baumgartner, 'Text–background polarity affects performance irrespective of ambient illumination', Ergonomics (2007)
- Piepenbrock et al., 'Positive Display Polarity Is Advantageous for Both Younger and Older Adults', Ergonomics (2014)
- IBM Carbon Design — Dark Theme white paper (contrast amplification rationale)
Applies To
- dark-mode token derivation (don't naive-invert)
- weight selection: bump body weight from 400 → 450/500 in dark themes
- OKLCH lightness tuning when mirroring light tokens to dark
- checking that AA-passing light tokens still pass when inverted
Quantitative
- Contrast Amplification Factor: ≈ 1.1× (10%)
- Weight Amplification: +50 weight units typical (e.g., 400 → 450)
- Halation Mechanism: subpixel rendering + LCD photon scatter on adjacent dark pixels
Counter Conditions
- OLED displays with true blacks reduce halation considerably — amplification factor closer to 1.0.
- Astigmatism users report inverse polarity preference — halation is more pronounced for them, but the discomfort flips relative to the median user.
- Variable-font weight axes let dark-mode amplification be a continuous tweak rather than a discrete weight step.
Source
aoe-engine/examples/frontend-design/primes/compiled/@community/fact-contrast-amplification/atom.yaml