Mr. Mattis said that at the preview of the sale he tested it with a black light and found optical brighteners.

An interactive display demonstrates how you can tell whether a picture has had optical brighteners added to it to make it look older.

End uses of optical brighteners include:

Methylketol is used as an intermediate for synthesizing dyes, pigments, optical brighteners, and pharmaceuticals.

These agents include optical brighteners, fabric softeners, and colourants.

Personnel have been instructed that the uniform must be washed with a mild detergent that does not contain "optical brighteners."

Fragrances, enzymes, optical brighteners and disinfectants must be listed on the product label in any concentration.

It is used on a large scale to prepare naphthalic anhydride, which is a precursor to dyes and optical brighteners.

Biphenyl is also an intermediate for the production of a host of other organic compounds such as emulsifiers, optical brighteners, crop protection products, and plastics.

Besides the fabric, some masks also included imported optical brighteners, which made some nominally white areas slightly blue.