Editing Optical brightener (section)

{{short description|Chemical compounds that absorb and re-emit light}}
[[Image:LaundrydetergentGlow.jpg|thumb|right|Laundry detergent [[fluorescing]] under ultraviolet light]]
'''Optical brighteners''', '''optical brightening agents''' ('''OBAs'''), '''fluorescent brightening agents''' ('''FBAs'''), or '''fluorescent whitening agents''' ('''FWAs'''),  are chemical compounds that absorb light in the [[ultraviolet]] and violet region (usually 340-370&nbsp;nm) of the [[electromagnetic spectrum]], and re-emit light in the blue region (typically 420-470&nbsp;nm) through the phenomenon of [[fluorescence]]. These additives are often used to enhance the appearance of color of [[textile|fabric]] and [[paper]], causing a "whitening" effect; they make intrinsically yellow/orange materials look less so, by compensating the deficit in blue and purple light reflected by the material, with the blue and purple optical emission of the fluorophore.<ref name=Ullmann>{{Ullmann|first1=Eduard|last1=Smulders|first2=Wolfgang|last2=Rybinski|first3=Eric|last3=Sung|first4=Wilfried|last4= Rähse|first5=Josef|last5=Steber|first6=Frederike |last6=Wiebel|first7= Anette|last7=Nordskog|title=Laundry Detergents|year=2002|doi=10.1002/14356007.a08_315.pub2}}</ref>