Samples should be fully conditioned, preferably to the same temperature and humidity as the standard they are being compared to. ASTM standard conditions are 70 F +/-2 and relative humidity of 65% +/-2%.
2. Spectrophotometer settings:
The spectrophotometer’s area view or aperture should be as large as the sample will allow and the settings for the UV and specular components should be the same as the standard.
3. Fabric presentation:
The sample should be folded until opaque. An average of four measurements, repositioning and rotating 90 degrees between each measurement, is sufficient for most flat fabrics but some substrates may require more measurements.