AATCC 6 pdf free download

AATCC 6 pdf free download.Instrumental Color Measurement.
2.3.8 All color measuring instniments require a white calibrated standard with which to standardize the instrument. The colorimetric values for this calibration standard are stored in the instniment or the software and require only that a specific standard be used to standardize the instrument. The correct white standard is usually identified with a serial number.
2.4 Standardization
2.4.1 Proper standardization of any color measuring instrument is absolutely necessary to achieve uniform, accurate results. While different types of instruments require varying methods of standardization, there are common principles which must be observed.
2.4.2 in general, an instrument standardization involves measuring a clean white surface of known reflectance factors (referenced to a perfect reflecting diffuser) and calculating (through software built into the instrument or computer program) a series of correction factors which will be applied to all subsequent measurements. Some instruments also require a black tile (or light trap), and possibly a gray tile. Each of these materials must be maintained in its original clean, unscratched condition. Refer to manufacturer’s recommendations for cleaning instructions.
2.4.3 The frequency with which this standardization must be performed depends on many factors including the type of instrument, the environmental conditions in vhjch the instrument operates, and the required accuracy of the results. For most applications. an interval of 2-4 h is typical.
2.4.4 Once the standardization step has been performed, it is important to verify the success of the procedure by measuring some colored materials (‘eritication standards) and comparing the resulting colorimetric values to the original values for these materials. If the measured values do not fall within an acceptable variation from their original values, the Standardization is not considered valid. The number of verification standards and the acceptability limits depend on user requirements. but are typically 1-3 standards and an acceptance limit of 0.20 (2: 1) (D/ I 0°) units.
2.5 Sampling
2.5.1 All measurements taken on color measuring instrumentation involve “sampling.” The area-of-view of the instrument, the number of presentations averaged to produce a single measurement, the difficulty of presenting the specimen to the instrument, and the accuracy with which the sample represents the object of concern (garment, roll, dye lot, etc.) all play important parts in achieving meaningful and reproducible results. Refer to ASTM Test Method E 1345 (see 7.1) and SAE Test Method J1545 (see
7.3) for techniques in establishing sampling procedures.
2.6 Specimen Preparation
2.6.1 The ideal specimen to measure is a rigid, non-textured, inert, opaque specimen of uniform color. Such ideal specimens do not exist in textiles, so it becomes necessary to employ techniques and practices when measuring most textile materials which eliminate or reduce the effect any objectionable characteristics have on the instrumental color measurement. Specific procedures and techniques for handling specimens which meet the following characteristics are presented in the Appendix.
2.6.2 Fluorescence of the specimen (from dyes or fluorescent whitening agents [FWAsJ) will influence the results depending on the amount of fluorescing material present and the amount and quality of ultraviolet and visible energy in the instrument light source. Results may be particularly hard to duplicate between instruments. Example materials are white or lightly colored materials treated with FWAs.AATCC 6  pdf download.