ISO 22754:2008规定了通过红外反射测量测定有效残余油墨浓度（埃里克数）的方法。 ISO 22754:2008适用于所有类型的脱墨再生纸浆，以及残留油墨为黑色的再生纸浆制成的机械纸。仅当950 nm处的不透明度小于97%时，该方法才适用于片状材料。获得的ERIC数取决于油墨颗粒大小的分布，该方法对亚微米颗粒最有效。只有当测试材料的油墨分布、形成和克数均匀，从而将纸张的不同部分呈现在反射计的测量孔上，产生非常相似的读数时，所得值才是可靠的。

ISO 22754:2008 specifies a method for the determination of the effective residual ink concentration (ERIC number) by infrared reflectance measurement. ISO 22754:2008 is applicable to all types of deinked, recycled pulp and to sheets of machine-made paper made from recycled pulp, where the residual ink is black. The method is applicable to materials available in sheet form only if the opacity at 950 nm is less than 97 %. The ERIC number obtained is dependent on the distribution of ink particle sizes, and the method is most effective for submicron particles. The value obtained is reliable only if the test material is uniform in ink distribution, formation, and grammage such that presenting different parts of the sheet to the measuring aperture of the reflectometer produces very similar readings.