Size Estimation Chart (Transparency)

The TAPPI Size Estimation Chart, is a transparent chart used to measure the size of spots, defects, or inclusions over the range of 0.02 to 5.00 square millimeters 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. These charts also serve as quality assurance resources to determine the size of imperfections in medical tubing, plastics and other materials.
The charts are manufactured from an original negative produced on DuPont CRR film. A rapid-access processor using Kodak/Fujifilm chemistry is used for processing the transparencies. Each film positive is produced on Kodak Contact 2000 film, using a NuArc contacting frame with an NuArc light source and NuArc light integrator which controls the exposure. The cards are exposed to 20 units of light. To measure the accuracy of the end product, each transparency is measured by looking at the .2 dot with a 100-power magnifier that has a reticle (scale), incremented in 5/10,000’s of a millimeter, on the lens. The dots on the chart are correct within an average 10% or 0.005 square millimeters, whichever is the larger.
You may also be interested in TAPPI’s Dirt Estimation Charts. TAPPI’s Dirt Charts are manufactured from an original negative produced on DuPont CRR film and estimate the equivalent black area (EBA) of dirt or other colored specks in conjunction with T 213 or T 437 or use image analysis, T 563, for EBA measurement in paper and paperboard.