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filmscanners: NikonScan 3.1: how to get good color and shadow detail



Greetings scanners--

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 
monitor.

Yours for better scanning,

--Bill


========================================================================
TIP-1: To get the best shadow detail go to the Color Management 
preferences and turn OFF Nikon Color Management.

DISCUSSION:

(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.

DISCUSSION:

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.

DISCUSSION:

(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&LS40v3.1.0.3000".  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 
"Positive" setting.









-- 

======================================================================
Bill Fernandez  *  User Interface Architect  *  Bill Fernandez Design

(505) 346-3080  *  bill@billfernandez.com  *  http://billfernandez.com
======================================================================




 




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