该方法提供了一种测定废纸脱墨浆中有效残余油墨浓度（ERIC）的方法。油墨的存在会影响再生纸的亮度和颜色。微量的残余油墨会使再生纸比原浆制成的纸更暗、更灰，然而，如果大部分油墨已被去除，故意漂白或脱墨化学品附带漂白可以恢复一些亮度损失。如果能监测油墨的有效浓度，就可以更容易地抵消残余油墨的着色力。 亮度不仅受油墨的影响，还受木质素和染料等可见光波长吸收剂的影响。因此，亮度被认为是监测脱墨过程的一种无效方法。ERIC方法在光谱的红外区域使用反射率测量，其中油墨的吸收系数比纤维和其他成分的吸收系数大几个数量级，从而形成了一种测定油墨浓度的灵敏方法（1）。 ERIC测量取决于油墨颗粒大小的分布，对亚微米颗粒最有效（2）。

This method provides a means for determining the Effective Residual Ink Concentration (ERIC) in deinked pulp and paper made from recycled feedstock. The presence of ink influences the brightness and color of recycled paper. Trace amounts of residual ink can leave recycled paper darker and grayer than paper made from virgin pulp, however, deliberate bleaching or incidental bleaching by deinking chemicals can recover some brightness loss if most of the ink has been removed. Counteracting the tinting power of residual ink can be easier if one can monitor the effective concentration of the ink. Brightness is not only affected by the presence of ink but also by other absorbers of visible wavelengths of light such as lignin and dye. For this reason, brightness has been found to be an ineffective way to monitor the deinking process. The ERIC method employs reflectance measurements in the infrared region of the spectrum where the absorption coefficient for the ink is several orders of magnitude greater than the absorption coefficient for the fiber and other components, resulting in a sensitive means for determining the concentration of ink (1). The ERIC measurement is dependent on the distribution of ink particle sizes and is most effective for submicron particles (2).