This part specifies the preparation, use and colour reactions of Lofton-Merritt stain. It should be used in conjunction with ISO 9184-1 and, if necessary, with other staining tests defined in ISO 9184-2. The Lofton-Merritt staining test is applicable to the qualitative and quantitative differentiation of unbleached and bleached softwood chemical pulps, unbleached kraft and sulfite in softwood pulps, unbleached semi-chemical kraft and sulfite pulps.