AATCC 110:2015 pdf download.Whiteness of Textiles
5.3 When employing measuring instru- ments that are not equipped with capabil- ities for calibrating the UV content of the specimen illumination, the formulas pro- vide for relative evaluations of whiteness that are restricted to specimens measured on the same instrument at nearly the same time. When employing measuring instru- ments that are equipped with capabilities for calibrating the UV content of the specimen illumination, the formulas pro- vide evaluations of whiteness that can be directly compared to results from simi- larly calibrated instruments and that are adequate for commercial use.
6. Apparatus and Materials
6.1 Color Measuring Instrument. A re- flectance spectrophotometer or colorime- ter capable of measuring or calculating CIE tristimulus values with at least one of the CIE specified geometries (45/0, 0/45, diffuse/0, 0/diffuse). When integrating spheres are used for measuring fluores- cent specimens, the spectral power distri- bution of the illuminating system is al- tered by the reflected and emitted power from the specimen. The use of the 45/0 or 0/45 condition is therefore preferable (see 12.1). To be able to make direct compari- sons between results from different in- struments, identical measuring geome- tries should be used and all instruments should have the capability of adjusting the amount of ultraviolet energy in the il- lumination source.
6.2 Reference Standard. The primary standard is the perfect reflecting diffuser (see 3.4). Secondary Reference Standards are standards that are calibrated in terms of the perfect reflecting diffuser and are used in the standardization of the instru- ment. 6.3 UV Lamp. Used for visual determi- nation of presence of FWA on textile specimens.
8.1 Before proceeding with color mea- surements, determine whether or not a fabric contains FWA by viewing a speci- men in a dark room under ultraviolet light. A fabric that contains FWA will fluoresce under the UV light.
8.1.1 If fluorescent whitening agents (FWA) are present on the textile material, the measurement must be made with an instrument that illuminates the specimen with polychromatic light (full spectrum) and has a relative spectral power distribu- tion approximating CIE illuminant D 65 from 330-700 nm. Consult instrument manufacturers for suitable equipment. The user should also verify the suitability of the instrument if flash illumination is being used.AATCC 110 pdf download.