The process in which a precipitant is added incrementally to a highly dilute polymer solution and the intensity of light scattered by, or the turbidity due to, the finely dispersed particles of the polymer-rich phase is measured as a function of the amount of precipitant added.
Source:
Purple Book, 1st ed., p. 67 (http://old.iupac.org/publications/books/author/metanomski.html)