ABSTRACT
The human eye has limitations in resolution and contrast levels that must also be considered when viewing diagnostic information in a radiograph. The critical factors are:
The units commonly used to describe light intensities depend on the source. For example, when measuring the amount of light emanating from a view box or a video monitor the luminance is measured in SI units of candela m2 (or nits in the m.k.s. system). A table of values is given in Table 8.1 comparing SI and non-SI values.
