Understanding NRT- Reading 1- 2 of 2- Radiogaphic Testing A
Understanding nrt reading 1- 2 of 2- radiogaphic testing a
Understanding nrt reading 1- 2 of 2- radiogaphic testing a
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Chapter 12: Radiographic Density<br />
Film speed, gradient, and graininess are all responsible for the performance<br />
<strong>of</strong> the film during exposure and processing. As these combine with<br />
processing variables a final product or the radiograph is produced. In viewing<br />
the radiograph, requirements have been established for acceptable<br />
radiographs in industry. The density <strong>of</strong> a radiograph in industry will determine<br />
if further viewing is possible.<br />
Density considerations date back to early day radiography. Hurder and<br />
Drifield have been credited with developing much <strong>of</strong> the early information on<br />
the characteristic curve and density <strong>of</strong> a radiograph. Codes and standards will<br />
typically require densities <strong>of</strong> a radiograph to be maintained between 1.8 to 4.0<br />
H&D (Hurder and Drifield) for acceptable viewing. As density increases,<br />
contrast will also increase.<br />
Charlie Chong/ Fion Zhang
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