Metadata: EXPO field

EXPO stands for exposure and indicates the film exposure quality. Possible values are "N" (normal), "U" (under-exposed), "O" (over-exposed), "F" (out of focus).

The qualitative nature of this field leads to subjectiveness in the data. There is no distinction between extreme or slightly underexposed/overexposed.

This field is not being cataloged beginning with STS093 (July 1999).