该方法适用于纸张和纸板的光学字符识别（OCR）清洁度的数值估计，即污垢、斑点或标记的频率。有关其他污垢计数方法，请参阅TAPPI T 437纸和纸板中的污垢、TAPPI T 213纸浆中的污垢，以及TAPPI T 563，等效黑色面积（EBA）和通过图像分析对纸浆、纸张和纸板中可见污垢的计数。该方法可用于要求单位面积上的斑点数量而非等效黑色面积的应用中。在这种方法中，无论大小、形状或颜色如何，每个污点都会单独计数。这与TAPPI T 437不同，在TAPPI T 437中，污垢以等效的黑色面积表示，并且是其颜色、与背景的对比度和形状的函数。

This method is suited for the numerical estimation of cleanliness for optical character recognition(OCR) purposes of paper and paperboard in terms of the frequency of dirt, specks, or marks. For other dirt count methods, see TAPPI T 437 Dirt in Paper and Paperboard, TAPPI T 213 Dirt in Pulp, and TAPPI T 563, Equivalent Black Area (EBA) and Count of Visible Dirt in Pulp, Paper and Paperboard by Image Analysis.This method may be used in applications where the number of specks per unit area rather than the equivalent black area is required.In this method, each dirt speck is counted individually regardless of size, shape, or color. This differs from TAPPI T 437 where the dirt is expressed in terms of equivalent black area and is a function of its color, contrast with the background, and shape.