W3C APCA 0.98G — DISPLAY ERGONOMICS & ACR CALCULATOR

APCA Perceptual & Ambient Display Contrast Tool

Evaluate text readability using W3C APCA 0.98G perceptual lightness contrast ($L_c$ score), WCAG 2.1 relative luminance ratios, font size & weight recommendations, and physical Ambient Contrast Ratio (ACR) under room glare.

ÉVALUATEUR ERGONOMIQUE W3C APCA 0.98G ET WCAG 2.1

Inspecteur de Contraste Perceptuel et Ambiant APCA

Contraste de clarté ($L_c$), perte due aux reflets et risque de halo pour astigmates.

LISIBILITÉ OPTIMALE (Lc ≥ 75)

🎨 CONTRÔLES COULEUR, POLICE ET AMBIANCE

Couleur du Texte

Arrière-plan

Préréglages Rapides

Graisse de Police

Taille de Police

Technologie de Dalle

Réflectance de l'Écran

Éclairement Ambiant de la Pièce :300 Lux

10 Lux (Sombre)300 Lux (Bureau)2000 Lux (Plein Soleil)

Luminance Maximale de l'Écran :350 Nits

80 Nits (Faible)350 Nits (Standard)1000 Nits (HDR)

📊 RÉSULTATS DE CONTRASTE ET ERGONOMIERISQUE D'ASTIGMATISME : LOW

Contraste APCA

Lc -82.4

Texte clair sur fond sombre

Ratio WCAG 2.1

14.85:1

AAA Pass (Normal)

ACR Ambiant

145.2:1

92.7% Perte par Reflet

Aperçu Typographique en Direct

Étalonnage du Contraste Perceptuel d'Écran

Portez ce vieux whisky au juge blond qui fume. L'APCA 0.98G évalue le contraste ($L_c$) selon la sensibilité humaine aux fréquences spatiales, la graisse et les reflets.

📏 Recommandation Typographique APCA :Min 14px @ Weight 400

Conformité WCAG 2.1

Normal Text AA (≥4.5):PASS

Normal Text AAA (≥7.0):PASS

Large Text AA (≥3.0):PASS

Reflet et Niveau de Noir

Noir Perçu :0.05 Nits

Niveau d'Éblouissement :Moderate

Recommandations Ergonomiques :

Le contraste actuel satisfait le seuil recommandé APCA ($L_c \ge 75$) pour le corps de texte.

Browser & OS Color Management Limitations

Software-based visual evaluation patterns are subject to Web browser color space mapping (sRGB / Display P3), operating system display scaling, ICC profile overrides, and GPU driver settings. While Display Test Online utilizes hardware-accelerated WebGL 2.0 rendering pipelines, browser-based tests cannot fully replace physical hardware colorimeters or spectrophotometers (e.g., Calbrite Display Plus HL, X-Rite i1Display Pro) for color-critical prepress workflows.

OPTOMETRIC ERGONOMICS & NON-MEDICAL NOTICE

Display Test Online is an engineering calibration utility for electronic visual displays (LCD, OLED, QD-OLED, MicroLED) and mobile touch digitizers. This software is NOT a medical eye exam, optometric vision test, or diagnostic health utility.

To reduce Digital Eye Strain (DES) during display calibration, apply optometric ergonomics:

The 20-20-20 Rule: Every 20 minutes, look at an object at least 20 feet away for 20 seconds.
Ambient Illumination: Ensure room ambient lighting matches display brightness levels (~100–150 nits for standard SDR workloads).
Optimal Viewing Distance: Place your screen approximately 20 to 30 inches (50–75 cm) from your eyes.

Frequently Asked Questions

What is APCA lightness contrast (Lc score)?

APCA (Advanced Perceptual Contrast Algorithm) 0.98G is the W3C candidate standard for perceptual contrast. Unlike legacy WCAG 2.1 4.5:1 ratios, APCA calculates contrast dynamically based on spatial frequency, font weight, background polarity, and human vision non-linearities.

How does ambient room lighting affect display contrast?

Room ambient illuminance (lux) reflects off screen surfaces, creating glare that elevates perceived black levels. Under 300 lux office lighting, a 1,000:1 IPS display can drop to an effective Ambient Contrast Ratio (ACR) of under 150:1.

Why does dark mode white text cause haloing or astigmatic fatigue?

Pure white text (#FFFFFF) on pitch-black canvas (#000000) creates high-luminance contrast edge clipping that worsens astigmatism halation. APCA recommends off-white text (#E2E8F0) on charcoal dark backgrounds (#121215).