• David Newman

3 interesting things to know about 'Shading' & 'Pooling'

Let's talk about shading, or what is called pooling in some cases. This is a condition where visible large blotches or areas that appear to be a darker or lighter color than the surrounding area. This appearance will reverse from opposite views in most circumstances, and is not due to an actual change in color, opposed to what many may believe. It is actually due to the different direction of the surface pile of the fabric in question, altering the way light reflects off the respective areas. See the reverse affect photos below...

1: The International Organization of Standardization [# ISO 2424] defines shading as a change in appearance due to localized alterations in the orientation of the fibers, tufts, or loops. There is no actual change in hue, just a difference in light reflection. Shading is defined in three grades; Tracking, Pile Reversal, and Temporary Shading.

Example of Tracking. Notices the stripes reverse dark and light from opposite views...

Example of Pile Reversal, or what is often called pooling as it looks as if someone spilled water on the flooring. Notice that this condition reverses from opposite views...

Example of Temporary Shading to the fabric of 2 cushions. Notice how they both appear to be the same overall shade of color in the left photo, but the design to the left cushion appears darker in the right photo, after turning the cushion 180°...

2: The Carpet & Rug Institute (CRI) states the following in a technical bulletin on shading:

All pile yarn carpet is subject to pile reversal; however, it is most likely to be observed in smooth surfaced, densely constructed, plush type qualities. This phenomenon is difficult, if not impossible, to predict or prevent. Pile reversal is not a manufacturing defect and does not affect the durability of the carpet. Pile reversal is not due to the materials used to produce the carpet, the manufacturing process, or any combination of these factors. Shading may develop on a carpet made with any fiber or manufacturing process.

3: I recall a seminar on carpeting back in the mid-80s, where the instructor had an excerpt from a book published in the 1800s which was discussing this same shading phenomenon to rugs! This condition has been around as long as we have been using textiles. It can be found on textile floor coverings, textile fabrics used in upholstery, and tapestries. I have corrected this condition a multitude of times, by applying steam vapor to the carpet or fabric and grooming the surface pile so that it all runs in the same direction. The problem is the condition always reappears after being put back into use.

This shading condition is not a manufacturing defect or flaw, it is a characteristic which can occur on various textiles, but does seem to be more prevalent to plush or velvet style, cut pile, textiles.

Check out this photo! It's showing tracking affecting 2 different carpets, of different constructions, from different manufacturer's, installed a few years apart!

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