The color change shall be measured according to ISO 7724-1 or SAE J1545 (CIELAB color space, 10 degrees
observer, metering orifice ≤10 mm, Illuminant D65, specular component included).
Visual evaluation by the Design Responsible Engineer and GM Materials Engineer shall override the
measured value in cases of disagreement. Component level natural weathering can and should substitute for
component level accelerated weathering whenever possible