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).