mnthiraviam,
Density and sensitivity are two different things. Density is a measure of the darkness of a radiograph. Sensitivity is the measure of the smallest detail which can be detected. Sensitivity is gaged by the penetrameter. That said, if the density of a radiograph is extremely light or dark it is more difficult (or impossible) to see the required penetramter thus affecting the measure of sensitivity.
Different specifications have different requirements for density. A common acceptable range of densities is 1.8 to 4.0. The density (or darkness) of the radiograph can vary throughout the radiograph depending on factors such as part thickness variation, part curvature and weld reinforcement. Some specifications have an additional requirement that the density of the radiograph at the location of the penetrameter must be close to the density in the area of interest. This requirement assures a potential variation in density would not affect the ability to see a defect based on the visibility of the penetrameter. Typical specification range for variation is the density of the area of interest can be +15% / -30% to the density at the penetrameter.
JR97
