A fluorescent substance added to detergents in order to produce a whitening effect on laundry.
- ‘Arches Bright White is created without optical brighteners or bleaches with only the purest well water and cotton fibers, company officials said.’
- ‘Softeners, optical brighteners, and antistatic agents also may be used on some fabrics.’
- ‘I have read that long wash times can leach out optical brighteners, but I've never been able to tell the difference between 2 and 6 hours in a cold wash.’
- ‘As a result, the materials that contain optical brighteners appear to reflect more light than is incident upon them and the blue-violet emission tends to offset yellowish reflected light making the material appear whiter.’