Classification depends on the pulping process used at the mill, not on the fiber species or bleaching stage. Sulfite pulp is produced using acidic or bisulfite cooking liquors, while kraft and soda pulps use alkaline liquors. Mill documentation identifying the cooking process is the definitive basis for choosing between the two headings.

Sulfite pulp's lower lignin content and finer fiber structure make it preferred for high-absorbency tissue, glassine and greaseproof papers, and certain specialty printing grades where softness or transparency is required. Its lower strength compared to kraft limits its use in packaging applications that demand high tear resistance.