Fényállóság

Fényállóság, often translated as lightfastness or colorfastness to light, refers to the resistance of a colored material, such as a pigment, dye, or ink, to fading or color change when exposed to light. This property is crucial for many applications where the longevity of color is important, including textiles, paints, printing inks, and artistic materials.

The degree of lightfastness is typically measured using standardized tests, often involving exposure to artificial light sources that simulate sunlight under controlled conditions. These tests result in a rating system, which can vary depending on the industry and the specific standard being used. For instance, in the art world, the Blue Wool Scale is a common method, where a rating of 8 indicates excellent lightfastness, and lower numbers suggest susceptibility to fading.

Factors influencing lightfastness include the chemical structure of the colorant, the concentration of the colorant, the presence of other substances in the material, and the intensity and duration of light exposure. Some colorants are inherently more stable to light than others. UV radiation in sunlight is a primary driver of fading, as it can break down the chemical bonds within the color molecules, leading to a loss of color intensity or a shift in hue.

Understanding and ensuring adequate lightfastness is essential for product quality and consumer satisfaction, particularly for items expected to maintain their appearance over extended periods.