For use in analytical methods, which determine or identify particulate constituents of a mixture irrespective of the amount present. Qualitative filter papers are often used in routine separation work that still requires high purity and consistent performance. This fast filtering grade, with extremely high loading capacity, is recommended for the filtration of coarse and gelatinous precipitates. The creped surface of Ahlstrom 961 also offers higher surface area to increase filtration speed.