该透明度由TAPPI污垢评估表开发并基于该表，用于测量纸张和其他工业材料（如纺织品或塑料）中0.02至5.00 mm2范围内的斑点、缺陷或夹杂物的大小。TAPPI试验方法T 564概述了这种透明度的使用说明。该图表可用于大量需要通过直接比较已知面积的磁盘或矩形来估计大小（面积）的应用中。应用可能包括但不限于测量印刷表面上的可见油墨飞溅，估计生物材料的生长速率- 菌落、透明塑料铸件和薄膜中的空气夹杂物等。该图表不得用于估算污垢或其他有色斑点的等效黑色面积（EBA）（将TAPPI污垢估算图表与T 213或T 437结合使用，或使用图像分析，T 563进行EBA测量）。

Developed from and based on the TAPPI Dirt Estimation Chart, this transparency is used to measure the size of spots, defects, or inclusions over the range of 0.02 to 5.00 mm2 in paper and other industrial materials such as textiles or plastics.Instructions for use of this transparency are outlined in TAPPI Test Method T 564.The chart can be used in a large number of applications where there is a need to estimate a size (area) by way of a direct comparison to a known area disk or rectangle. Applications may include, but are not limited to, the measurement of visible ink spatter on printed surfaces, the estimation of the growth rate of bio-colonies, air inclusions in transparent plastic castings and films, etc. The chart must not be used to estimate the equivalent black area (EBA) of dirt or other colored specks (use the TAPPI Dirt Estimation Chart in conjunction with T 213 or T 437 or use image analysis, T 563 for EBA measurement).