In coatings, brightener molecules lose much of their effect when they clump together. A carrier like polyvinyl alcohol, starch or CMC keeps them separated in a favorable state, raising whiteness from the same dose and pushing the greening point higher. Coating chemists raise carrier level before they add more brightener.
Heard on the job
Before you add more OBA to the top coat, try another half part of carrier; it usually gets us four or five CIE units.
Also heard as
- OBA carrier
- brightener carrier
Related terms
OBA
Optical brightening agent: a dye that absorbs UV light and re-emits it as blue, making paper look whiter.
Greening
The greenish cast a sheet takes on when optical brightener is dosed past its effective range.
Coat weight
Mass of dry coating applied to paper per unit area, usually stated per side in grams per square meter.