CEN/TS 14159:2014:
Fromt CEN/TS 14159:2014 it apperas a.o.t:Shading:
The concept covers water-like spots in the carpet which is due to an area determined change in the original pile direction. This phenomenon is likely to be seen in velour qualities. Depending on light sources and light influences, dark areas that deviate from the general expression may appear. This is not a production fault and is as such not acceptable as a valid claim.
Pile reversal:
This is seen in a clearly defined area where a change in the pile direction compared to the original pile direction appears. The optical effect by this change is more visible than by shading, as mentioned above. The reason for this phenomenon is not known and not considered as a production fault and is as such not acceptable as a valid claim.