Yellowing

Q: Sometimes my customers return white garments and say they are now yellow or not as white as they were before cleaning. I do not believe it is redeposition, since I maintain my solvent carefully. So, what else could be dulling the brightness of these white fabrics?

A: Assuming the discoloration is not redeposition, the most likely cause of yellowing is a breakdown of a fabric finish used to make it whiter and brighter. Bright white is not really a natural shade of fibers, yarns, and fabrics. Many times, manufacturers brighten and whiten fabrics by the use of special fluorescent whitening agents or optical brighteners. Some of these brightening finishes have a somewhat limited durability to conditions of consumer use and storage. These finishes can yellow when exposed to light and atmospheric gases. The areas of a garment that receive more light exposure may show a more pronounced discoloration. In some cases, an entire garment may turn yellow or off-white. Drycleaning can sometimes accelerate this process. This change may not be due to any improper drycleaning procedure. It should be pointed out that almost all white fabrics will eventually yellow to some degree from oxidation of the original finish, storage, and care.

Suggested Reading
DLI Standard, Gold, and Premier members may access more information on this topic in the following bulletins available in DLI's Encyclopedia of Drycleaning Online:

• Technical Operating Information (TOI) 661: Yellowing In Storage
• TABS No. 406: White Fabric Turns Yellow
• TABS No. 394: Yellow Streaks in Drapes