With this image, grain is slightly reduced with
every increment in which GEM is increased and is virtually
eliminated when GEM is set to 4. Unfortunately sharpness is
also loss as the GEM settings are increased. It should also
be noted that the effects of GEM seem to vary between images
so images shot on different film or different exposure settings
will not respond the same way this image did. For images with
more pronounced grain, the effectiveness of GEM will be more
dramatic as the GEM level is increased. Many images will also
show artifacting from the use of GEM which is not seen here.
These artifacts resemble a crumpled plastic surface when GEM
is set too high.
CONCLUSION: Considering all the above, it is
recommended that GEM be set to off by default but used when
necessary by experimenting with the different levels to find
the setting that offers the best compromise between grain,
sharpness, and artifacting. Be careful to examine the effects
of GEM on the final scan and not the preview since Nikon Scan
does not accurately show the effects of GEM on the preview.