times on white or pastel linen or cotton garments I notice a general yellowing
after cleaning. I then wetclean many of these with no results. My ultra-violet
light does not indicate any brightener or fluorescent dye breakdown. What could
cellulose fabrics, such as rayon, cotton, linen, and ramie, are soft by nature,
so they are usually sized by finishes that impart body and luster. Often, these
sizings will oxidize with age and begin to discolor. A variety of chemical
finishes are used in manufacturing to achieve the desired shade, drape, and
Some of these chemical sizings and
starches tend to absorb oxygen and atmospheric gases from the air over time and
thus turn yellow. Objectionable discoloration can occur rapidly on some
fabrics, while others turn yellow only after prolonged use and storage.
However, the heat of drying and/or steam finishing after cleaning can
accelerate this type of oxidation of the finish, so the shade change may be
more noticeable after cleaning.
Unfortunately, in a case of oxidation
of sizing, there is usually no safe and effective method of restoration.
Caption: This item shows the breakdown of fluorescent whitening agents.