fehérségindex

The **fehérségindex** (literally "whiteness index") is a numerical scale used primarily in the textile and dyeing industries to quantify the degree of whiteness in fabrics or materials. It provides a standardized method for assessing how close a fabric appears to pure white under specific lighting conditions, typically daylight or a controlled light source. The index is particularly useful in quality control, ensuring consistency in production and meeting consumer expectations for brightness and cleanliness.

The calculation of the fehérségindex is based on spectrophotometric measurements, which analyze the fabric’s reflectance across a range of wavelengths in the visible light spectrum. The most common method employs the **CIE (Commission Internationale de l'Éclairage) whiteness index**, which incorporates both the brightness and the chromaticity of the sample. The formula accounts for the fabric’s reflectance at specific wavelengths (often 457 nm for blue and 578 nm for yellow) and compares it to a perfect white reference. Higher values indicate greater whiteness, with the maximum possible score typically around 100 for a truly white sample.

In practice, the fehérségindex is applied to various materials, including cotton, linen, and synthetic fibers, to evaluate dyeing processes, bleaching treatments, or the effects of washing. It helps manufacturers optimize production parameters to achieve desired whiteness levels while minimizing costs. The index is also relevant in environmental assessments, as it can reflect the efficiency of water and chemical usage in textile processing.

While the fehérségindex provides a useful quantitative measure, it is important to note that human perception of whiteness can vary based on individual preferences and lighting conditions. Thus, the index serves as a practical tool for objective comparison rather than an absolute standard of visual whiteness.