Editing Optical brightener (section)

==Common uses==
Brighteners are commonly added to [[laundry detergent]]s to make the clothes appear cleaner.  Normally cleaned laundry appears yellowish, which consumers do not like.<ref name=U2/>  Optical brighteners have replaced [[Bluing (fabric)|bluing]] which was formerly used to produce the same effect.

Brighteners are used in many papers, especially high brightness papers, resulting in their strongly fluorescent appearance under UV illumination.  Paper brightness is typically measured at 457&nbsp;nm, well within the fluorescent activity range of brighteners.<ref>{{cite web |author1=Printer Technical Service |title=Understanding Paper Brightness |url=https://cdn-s3.sappi.com/s3fs-public/sappietc/Understanding%20Paper%20Brightness.pdf |website=sappi/etc |access-date=5 November 2018}}</ref> Paper used for banknotes does not contain optical brighteners, so a common method for detecting [[counterfeit]] notes is to check for fluorescence.

Optical brighteners have also found use in [[cosmetics]].  One application is to formulas for washing and conditioning grey or blonde hair, where the brightener can not only increase the luminance and sparkle of the hair, but can also correct dull, yellowish discoloration without darkening the hair.  Some advanced face and eye powders contain optical brightener [[microsphere]]s that brighten shadowed or dark areas of the skin, such as "tired eyes".

End uses of optical brighteners include:
# Detergent whitener (instead of bluing agents)
# [[paper chemicals|Paper brightening]] ([[sizing|internal]] or in a [[coated paper|coating]])
# Fiber whitening (internal, added to polymer melts)
# Textile whitening (external, added to [[textile finishing|fabric finishes]])
# Color-correcting or brightening additive in advanced [[Cosmetics|cosmetic]] formulas ([[shampoo]]s, conditioners, eye makeup)