ACS Carpet Cleaning

Permanent Pile Reversal Shading Of Carpet


What is Permanent Pile Reversal Shading?

Permanent Pile Reversal Shading is a phenomenon that can appear in any cut pile carpet. Its occurrence is random and its causes are largely unexplained. It is also often referred to as watermarking, pooling or puddling.


A cut pile carpet that has ‘shaded’ will show areas lighter or darker than the surrounding carpet pile. This variation is caused by the reflection of light from pile tufts which come to lay in different directions (Diagram below).


To look at , Permanent Pile Reversal Shading is like the brushed appearance of other cut pile fabrics such as suede, velour and velvet.  However, the appearance change in a carpet that has ‘shaded’ will be permanent.

The degree of ‘shading’ seen will depend on the angle of viewing and the available light source.

Permanent Pile Reversal has been associated with cut pile carpet for many years, in fact well before the advent of machine made carpets.

Despite extensive research and development of methods and techniques to minimise the occurrence of shading, the characteristic is not predictable.

Other Phenomena That Can Be Mistaken For Permanent Pile Reversal

Tracking and footmarking may also appear in cut pile carpets but these are not permanent and should not be confused with Permanent Pile Reversal Shading.


Tracking Footmarking is seen as small localised marks on the carpet pile that are typically caused by dragging or scuffing associated with normal foot traffic.

The appearance change caused by footmarking is temporary and can be reversed by vacuuming or brushing of the pile fibres in the normal direction of pile lay.

Footmarking is a characteristic of most cut pile carpets and is not related to Permanent Pile Reversal Shading.

Tracking describes the flattening or crushing of the carpet pile in areas that receive more concentrated foot traffic than adjacent areas.

Tracking can appear in carpets of any construction and will depend on traffic patterns and the wear characteristics of the particular carpet that has been installed.


We Don\’t Know Much!

What is known about Permanent Pile Reversal Shading?

Despite extensive research and development of methods and techniques to minimise the occurrence of shading, the characteristic is not predictable. However, the consensus of expert opinion about Permanent Pile Reversal Shading is that:

  • It can occur in any cut pile carpet (or rug) including hand knotted, tufted, woven, bonded, knitted or hand-made carpets and rugs
  • It can occur in carpets made from all carpet fibres and blends of different fibres (e.g. nylon, wool, acrylic, polyester, polypropylene and their blends)
  • Its occurrence will not lead to premature wear of the carpet and it will have no effect on the durability of the carpet
  • It has not been linked to methods of installation.


Where does Permanent Pile Reversal Shading Occur?

Although research from around the world is inconclusive, location factors are thought to be linked to the incidence of Permanent Pile Reversal Shading.

Trials have shown that an installed carpet, showing no sign of Permanent Pile Reversal Shading, can develop the phenomenon when relaid in a shading-prone location.

However, it has not been possible to isolate the specific factors responsible although floor temperature, humidity, air currents, static electricity and earth rays have all been investigated as possible causes.


If your carpet has Permanent Pile Reversal Shading, it will not be corrected by cleaning the carpet.


Although the carpet will be evenly clean, because the pile is still reversed, Permanent Pile Reversal Shading will still be visible.

2 Responses

    1. Hi Lily.
      Shading is normally caused either by pile reversal which is a natural phenomenon, or by traffic wear. Neither is an issue that can be ‘undone’ by cleaning. Carpet cleaning can remove soils, spots and stains. Wear or other issues aren’t cleaning issues. It can be frustrating when an almost new carpet develops pile reversal shading. We see it every day. Unfortunately, if its not soiling, cleaning won’t get rid of it.

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