※ Textile Color Card GB GB / T251-2008 >> assessing staining Grey card >> ISO105 / A03-1993 Application: As a result of the international standard ISO, American standard AATCC and national standards required by GB of colorimetry Data standards calibrated gray card, so use the gray card assessing the color fastness grade, consistent with international. The gray cards for GB, ISO, AATCC, DIN, BS, JIS, color fastness rating Subject Matter and Scope EN standard: This standard specifies the color fastness of textiles assessment test sample card gray color change and methods of use. Accurate color measurement level gray card from the value of this can be used as a permanent record for the new production of the gray card and change in storage or use a gray card comparison purposes. Principle: ? Basic gray card by five pairs of matt gray small card (or burqa) composed, according to the distinguished color fastness is divided into five levels, namely 5,4,3,2,1. In each of the two levels and then add half a grade, namely 4-5, 3-4,2-3,1-2, it expanded into five nine stalls gray card. The first component of each pair are neutral gray, which only fastness Level 5 second composition is consistent with the first composition, the composition of each of the other second turn lighter, color progressively increases. Perception of color is determined by the color at all levels throughout the chromaticity defined as follows.