ANSI/TAPPI T 421 om-12

This method describes procedures which may be used for the qualitative determination and identification of the mineral constituents of filled and coated papers.

Due to the similarity in chemical composition and physical size and shape of some of the various possible constituents contained in a given paper specimen, more precise quantitative methods may at times be required for positive identification.

It is recommended that one become thoroughly familiar with this method by analyzing paper samples of known mineral component content.