What is a common cause of cellulosic browning in fabrics?

Cellulosic browning in fabrics is commonly associated with over wetting. When cellulosic fibers, such as those found in cotton and linen, become excessively wet, they can undergo a chemical reaction that leads to the formation of brown stains or discoloration. This browning occurs due to the breakdown of the cellulose fibers when they are saturated with moisture, particularly if the dried fabric is then subjected to high humidity or heat.

Over wetting not only allows the fibers to absorb too much water but can also result in the release of soluble impurities, which further contributes to visible staining. Proper cleaning techniques involve using the correct amount of moisture to minimize the risk of over wetting and its damaging effects.

The other options, while they may affect fabric in various ways, do not directly lead to cellulosic browning as effectively as over wetting does. Understanding the specific causes of browning is essential for upholstery cleaning technicians to avoid such issues during the cleaning process.