Pile Reversal

What do UFOs, Egyptian Pyramids, and pile reversal have in common? They are all unsolved phenomena, despite efforts from top experts. Though there is much that remains a mystery regarding pile reversal (also referred to as shading, pooling, or watermarking), it is beneficial to know more about it.

Carpet Shading Story

The expensive, light-colored saxony carpet you purchased has just been installed and it looks beautiful.  The carpet installers did a very nice job; the color compliments your furnishings perfectly and it feels so soft under your bare feet.  Life is wonderful!

One day, several months down the road, you notice a “spot” on the carpet that looks a little odd.  It is irregularly shaped and about two feet wide; if you had kids you would say, “OK, which one of you spilled and which one tried to wipe it up?”  But you do not have kids and there is no traffic in the area of the spot.  You remind yourself to vacuum more thoroughly. Even with an aggressive vacuuming schedule, the spoton your carpet keeps getting larger.  Worse, there are now similar areas showing up in other parts of the carpet.

You call the carpet retailer and he comes out and looks at the problem.  He says it is something called “shading” and it is not a manufacturing defect, rather it is a well-known characteristic of cut-pile carpets like yours.  He eventually sends you a brochure listing common carpet terms.  There, under the question “What is Shading?” you read:

“Shading is a change in pile direction that results in an apparent change in color due to the light reflecting in different ways.  Solid color cut-pile carpets will exhibit this more often than textured or patterned carpets.  Carpet shading is normal.  Severe cases of shading are also known as pooling or watermarking.  This results in a permanent pile reversal that occurs after installation.  It has no known cause and is usually confined to only certain areas of an installation.  Pooling or watermarking is not considered a manufacturing defect.”

Your heart sinks. Life is not so grand today.


Pile Reversal Phenomenon

When a cut-pile carpet is made, it will usually emerge with all the yarn tufts in the pile pointing in the same direction, therefore having a uniform appearance.  However, any shift in the orientation of the tufts will result in a visual change in the color of the carpet because light is reflected differently.  This apparent color change is broadly referred to as “shading.” 

Pile reversal, as described in our opening scenario, is a form of permanent shading. As previously mentioned, this problem goes by several other names as well: pooling, watermarking, pile switch and puddling.     

Pile reversal happens in cut-pile carpet constructions of all fiber types.   The phenomenon has been observed in tufted carpets and hand-woven silk Oriental rugs.  It can happen in newly installed carpets or it can occur after a more extended period.

What We Know About Pile Reversal

Though there is much that is still a mystery, there is a body of general information about pile reversal that can be useful.

  • It can occur in any cut-pile carpet, rug or mat, including tufted, woven, bonded, knitted or hand-made floor coverings.
  • It occurs in floor coverings of all fiber types, including blends.
  • There is no evidence to suggest a link between carpet manufacturing processes or components and pile reversal.
  • Certain locations can be conducive to pile reversal. There have been instances where an affected carpet was replaced with a totally different carpet, only to have the new carpet eventually develop the same problem.  The phenomenon has also been known to occur across carpet seams.
  • There is no proven correlation between the way a carpet is installed and any subsequent pile reversal.
  • There are no indications that pile reversal is associated with any maintenance method, or with topical treatments.
A Ray of Hope

Though most mills will not honor claims involving pile reversal because it has never been proven to be a manufacturing-related problem, there is at least one carpet mill that takes a different approach.  Brintons Carpets (UK), using a special process called “Brinset,” offers a twelve-month warranty against pile reversal on certain velvet styles.

Also encouraging, Wools of New Zealand has developed a technology called “Trutrac.”  This process is said to prevent pile reversal by permanently setting the carpet’s natural pile orientation through the use of controlled pressure.

Fiber-Seal's Efforts

Focusing on the care of high-end interior furnishings, including plush floor coverings, Fiber-Seal Service Centers have seen their share of unexplained pile reversal complaints over the years.  While we do not claim to be able to correct these problems, we continue to document them for further study.


If you have information on a pile reversal problem, we would like to hear from you.  Contact your local Service Center or e-mail us at info@fiberseal.com.  We will keep you apprised as new information becomes available.

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