Normally the exposure index ("S" value, EI, LgM) will indicate
if the receptor exposure level was appropriate. However, the
exposure index may not be correctly calculated if a histogram
analysis problem has occurred. Look at the chest area. Is
mottle present in the chest area. If mottle is present then
that is evidence that the exposure was low. However if the
chest area does not exhibit mottle, then the mottle below the
diaphragm may be the result to excessive "equalization" image
processing. Equalization processing can make light areas darker
and darker areas lighter. But if the lighter area represents
an under exposed area then the computer is trying to build an
image where the number of photons per pixel is very low and the
resultant image will be noisy (mottle).
Click on thumbnail to see larger image
Image failed to size correctly - adult chest on
35x43 film
Agfa image plate inserted in cassette the wrong
way round
Agfa image plate exposed from back of cassette
then reversed in post processing and side marker replaced incorrectly
(Lt sided tension pneumothorax)
Agfa image plate exposed from back of cassette
Kodak image plate exposed from back of cassette
Over aggressive black mask overlays scale on
lateral ceph image
