A carpet or rug may seem to change color in certain areas. When you look at the carpet from one angle, these areas can appear to be lighter than the rest of the carpet. Viewed from the other side, these spots appear darker. This condition is called shading.
Carpet pile has a natural slope in one direction. As long as the tufts slant in the same direction, the carpet has uniform color throughout. However, some of the tufts may slant against this normal pile lay, causing a variation in the way light is reflected from the napped surface...
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