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 circular area. 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 Size Estimation Charts are manufactured from an original negative on negative working contact film. The film positive is produced in a NuArc contacting frame with a NuArc light source and built-in light integrator which controls the exposure. Each piece of photographic film that is produced during the manufacturing process is evaluated with an X-Rite transmission densitometer for correct exposure.
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.
Calibrated Size Estimation Charts are ideal for quality assurance processes that require more exact measurement. Each transparent chart has 23 dots that are measured and documented within the specified tolerances. The actual measurements for each dot in square millimeters are exported to a Data Sheet with a unique serial number corresponding to the chart.
You may also be interested in TAPPI’s Dirt Estimation Charts. TAPPI’s Dirt Charts are opaque, 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.
Member: $57 List: $82