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.

可读性与感知对比度工程

APCA 感知对比度与环境眩光反射分析仪

基于 W3C WCAG 3.0 APCA 算法，评估高级感知对比度、空间频率及环境照明影响。

可读性黄金标准:

文字与背景色彩参数

文字颜色:

背景颜色:

快速预设方案:

字重粗细 (Weight):

字号大小 (px):

屏幕面板工艺与抗反射:

屏幕表面反射率:

环境光照度 (Lux):300 Lux

暗室环境 (0 lx)标准办公环境 (300 lx)户外强光/靠窗 (10,000 lx)

显示器峰值亮度 (Nits):350 Nits

暗光环境 (120 nits)标准亮度 (300 nits)高亮 HDR (1000 nits)

对比度与环境光效遥测数据散光眩光与晕影风险警告 LOW

APCA 感知亮度对比度 (Lc)

Lc -82.4

深底亮字模式 (暗色主题)

WCAG 2.1 传统对比度比例

14.85:1

AAA Pass (Normal)

环境对比度比值 (ACR)

145.2:1

92.7% 眩光对比度损耗率

动态排版渲染预览

工程级高辨识度文字排版

基于人眼视网膜对空间频率和亮度的感知模型，验证各类复杂光照下的长时间阅读舒适度。

建议最小字号与字重:Min 14px @ Weight 400

WCAG 2.1 达成级别:

Normal Text AA (≥4.5):PASS

Normal Text AAA (≥7.0):PASS

Large Text AA (≥3.0):PASS

眩光黑电平提升:

人眼感知纯黑亮度:0.05 Nits

环境眩光影响等级:Moderate

视力健康与工效学建议:

保持适宜的环境光照与文字对比度以保护视力。

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).