AATCC EP11:2016 pdf download.Spectrophotometer UV Energy Calibration Procedure for Optically Brightened Textiles
1. Scope
1.1 This evaluation pr(xedure describes the use of the Textile UV Calibration Standard (TUVCS) for inter-instrument calibration of UV content in the light source of spectrophotometers for the purpose of measuring white or light to medium colored textiles that have been optically brightened with a fluorescent whitening agent. UV absorption properties of fluorescent whitening agents (FWAs) used for textiles differ from those of FWAs used for plastics or other non-textile materials, necessitating the use of a different reference standard than those typically used for these other materials. This procedure is based on a semiannually replaced textile calibration stanthird that facilitates accurate UV content adjustment of the light source of spectrophotometers for use with textile materials independent of instrument geometry and the methodology used for adjusting the amount of UV energy in the instrument.
2. Principle
2. 1 The amount of UV energy in a spectrophotorneler light source is standardized by adjusting it (mechanically or by computation) until the calibrated value of the light source is in agreement with the CIE Whiteness Index (CIE WI) of the TUVCS (see 7.1).
4. Description of the Textile UV Calibration Standard
4.1 The TUVCS consists of a set of 4 layers of combed cotton broadcloth thai has been bleached, mercerized and treated with a specific formulation of optical brighteners. It measures 80 x 80 ± 5 mm and is attached to an opaque white. non-optically brightened blotting paper by staples on one edge. This facilitates the handling of the TUVCS without touching the portion that is to be used for measurement. It has been found that temperature and humidity changes of normal instrument operating ranges do not significantly alter the determined WI values. These changes are normally not in excess of 0. 1 WI. However, exposure to light can significantly deteriorate the FWA and cause changes in the WI. Therefore, it is important that the TUVCS be kept in its UV protective bag when not being used (see 7.4).AATCC EP11 pdf download.