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.

ENGENHARIA DE CONTRASTE E ACESSIBILIDADE

Analisador de Contraste Perceptual APCA e Reflexo

Baseado no algoritmo W3C WCAG 3.0 APCA para avaliar contraste perceptual e luz ambiente.

Padrão de Legibilidade:

Controles de Texto e Fundo

Cor do Texto:

Cor do Fundo:

Predefinições Rápidas:

Peso da Fonte:

Tamanho da Fonte (px):

Tecnologia e Revestimento do Painel:

Refletância da Tela:

Iluminação Ambiente (Lux):300 Lux

Ambiente Escuro (0 lx)Escritório Típico (300 lx)Luz Solar Direta (10.000 lx)

Luminância de Pico (Nits):350 Nits

Brilho Baixo (120 nits)Brilho Padrão (300 nits)HDR Alto Brilho (1000 nits)

Telemetria de Contraste e Luz AmbienteAviso de Risco de Halos/Astigmatismo LOW

Contraste Perceptual APCA (Lc)

Lc -82.4

Texto Claro em Fundo Escuro

Razão de Contraste WCAG 2.1

14.85:1

AAA Pass (Normal)

Razão de Contraste Ambiente (ACR)

145.2:1

92.7% Perda de Contraste por Reflexo

Pré-Visualização Tipográfica

Tipografia de Engenharia de Alto Contraste

Avaliação ergonômica de legibilidade e conforto visual para uso prolongado.

Tamanho Mínimo Recomendado:Min 14px @ Weight 400

Conformidade WCAG:

Normal Text AA (≥4.5):PASS

Normal Text AAA (≥7.0):PASS

Large Text AA (≥3.0):PASS

Nível de Preto com Reflexo:

Preto Percebido:0.05 Nits

Severidade do Reflexo:Moderate

Recomendações Ergonômicas:

Mantenha iluminação adequada para conforto visual.

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).