CONCLUSION: Contrary to expectations, making
adjustments in Nikon Scan was shown to provide worse results
than scanning images at maximum bit depth and adjusting them
in Photoshop. Also, there was no evidence to suggest that
making levels adjustments in the scanning software affects
the scanner in the analog domain. It would have to be concluded
from these results that the advice commonly circulated by
people and even websites
set up to offer scanning tutorials, is incorrect. These results
and conclusions are also consistent with statements
made by Ed Hamrick who developed Vuescan.
It should be noted though, that because this
is such an extreme example, most images will not show the
differences (if any) to be as dramatic as those seen here.
For the sake of working from a scan with the least amount
of post-processing applied to it though, it is still recommended
that all levels adjustments be made in Photoshop.