I've done more than 30 experiments with my new Nikon LS4000ED trying
to get the most shadow detail and best color from some very contrasty
Kodachrome slides. Here is what I've learned. Note that I'm using
NikonScan 3.1, Photoshop 6, MacOS 8.6 and a calibrated/profiled
Yours for better scanning,
TIP-1: To get the best shadow detail go to the Color Management
preferences and turn OFF Nikon Color Management.
(1) By default NikonScan is set up with color management ON and
outputs files directly to a profiled colorspace such as Adobe RGB.
However all of the available color spaces reduce the shadow detail.
(2) The "Scanner RGB" color space, which is supposed to mirror the
raw output of the scanner, produces scans that are dark and have
wierd color (what you'd expect from "raw" scanner data), but my
scanner profiler couldn't create a good profile with it, and I wasn't
able to pull useable shadow detail out of it using Levels.
(3) The "Wide Gamut (compensated)" color space has more shadow detail
than Adobe RGB, but not as much as with color management off.
(4) With color management off you still have to make the right choice
from the film-type menu: Negative, Positive or Kodachrome. The scans
come out with roughly the right colors and it makes a difference
whether you choose Positive or Kodachrome so obviously NikonScan is
doing some color correction of the raw data and making different
corrections for different film types.
(5) The resulting scans are low contrast but can easily be adjusted
with the Photoshop Levels dialog. Of course you want to scan in 14
bit (rather than 8 bit) mode so that you can make these tonal changes
without posterizing the image. After making tonal adjustments you
can downsample to 8 bits per pixel if you wish.
(6) Comparing two similar scans, one with color management on and
output to "Scanner RGB" space, the other with it off; if you adjust
the Levels to grossly lighten the shadows (to see just how much
detail you've got down there) you'll find that Scanner RGB seems to
have more tonal gradations in the deep shadows than the no color
management scan, but with a huge amount of very coarse and
color-shifted noise. Therefore the extra tonality of the Scanner RGB
scans is not useable for making pretty pictures, although it might be
useful for scientific or forensic use.
TIP-2: In NikonScan, after doing your preview scan, look at the
histogram in the Curves control panel. If the histogram doesn't
extend all the way to the right edge of the grid then go to the
Analog Gain control panel, bump up the analog gain and re-run the
preview. Repeat this until the right end of the histogram falls just
short of hitting the right edge of the grid.
This way you'll be able to utilize the full dynamic range of the
scanner and will get as much of the tonality as possible above the
scanner's CCD dark noise.
TIP-3: To get the best color, turn off color management in NikonScan
then make two scans of an IT8 color calibration target (such as the
Kodak Q-60). Make one scan with the film type set to "positive" and
the other with it set to "Kodachrome". Use your scanner profiling
software to make a profile of each scan (I use ICC Scan from
profilecity.com). Thereafter scan each "real" image with color
management OFF as described above, then in Photoshop "Assign" one of
your custom profiles to the image.
(1) If you don't want to create custom scanner profiles you can use
the generic one that Nikon supplies. In the Photoshop "Assign
Profile" dialog it's listed as "LS4000&LS40v220.127.116.1100". But your
custom ones will be much better.
(2) Be sure that if you scan with the film type set in NikonScan to
"Kodachrome" you use your Kodachrome custom profile. Same for the
Bill Fernandez * User Interface Architect * Bill Fernandez Design
(505) 346-3080 * firstname.lastname@example.org * http://billfernandez.com