Paper whiteness tester
This article provides a comprehensive overview of paper whiteness testers, including applicable standards, key parameters, operating principles, and test methodologies. Designed to measure the whiteness and brightness of paper, plastics, and textiles, these instruments ensure compliance with industry standards and quality control requirements.
Applicable Standards
The tester adheres to major international standards:
ISO: ISO 11475. ISO 2470-1. ISO 2470-2
TAPPI: T 56. T 452
GB/T: GB/T 7974. GB/T 8940.2
Main Parameters
| Parameter | Specification |
|---|---|
| Measurement Range | Whiteness: 0-100%; Brightness: 0-100% |
| Accuracy | ±0.1% (Whiteness), ±0.2% (Brightness) |
| Light Source | D65 (Standard Daylight Simulation) |
| Repeatability | ≤0.1% |
| Measurement Time | <2 seconds |
Working Principle
The tester employs a diffuse d/0° spectrophotometric method, using a D65 light source to simulate natural daylight. Sensors detect light reflected from the sample, which is analyzed to compute whiteness (W) and brightness (B) values. Advanced models integrate UV control to eliminate fluorescence interference.
Test Principle
Whiteness calculation follows the CIE (Commission Internationale de l'Éclairage) formula:
W = Y + 800(xₙ - x) + 1700(yₙ - y)
Where Y = tristimulus value, xₙ/yₙ = reference illuminant coordinates.
Brightness (B) is derived from light reflectance at 457 nm (R457), critical for assessing optical performance.
Applications
Ideal for paper mills, packaging, and textile industries, the tester supports R&D, quality inspection, and process optimization. Its compliance with global standards ensures reliable, reproducible results for both laboratory and field use.
This guide equips users with technical insights to select and utilize whiteness testers effectively, ensuring adherence to quality benchmarks.