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Robert D FeinmanOptimizing Color Negative Scans on Minolta
5400
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As has been pointed out in
several other topics here, the software that is provided with the
Minolta Elite 5400 and several other models is inadequate for
high quality scans of color negatives. Fortunately there is a
third-party solution: Vuescan from Hamrick software. By setting the parameters
within this software to capture all the dynamic range (clipping
levels set to zero) we get a scan that looks like this. |
 As Scanned |
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The image looks dark and
low in contrast. This is to be expected since the color negatives
have less maximum density and a smaller range of densities than
slide film. These settings have to
allow for the range of transparencies thus we are only using part
of the capture potential of the scanner. To avoid problems later on it may be a good idea to capture in 16 bits per channel. See my discussion of this
in another tip. |
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The simplest approach to
fixing this is to apply the auto adjustment in the curves or
levels dialog. Here is the result of
doing that. The contrast and brightness are much better, but the
image still appears a little flat and slightly bluish. |
 Auto Levels Applied |
| Notice
the tonalities are much better distributed over the range from
black to white. There is some posterization visible in the
histogram, since we are only using 8 bits per channel. This may
not be visible in the image, however. |
 Auto Levels Histogram |
| The
next approach is to set the black, white and gray points using
the eyedroppers in the curves dialog. We used the third from the left gray square in the bottom row for the neutral tone. The first square was used for the white point. The shadows behind the card were used for the black point. Once again the contrast is improved and the blue cast is removed. |
 Set Black, White & Gray Points |
This approach spreads the tones over a wider range than the auto levels approach. This can be adjusted by changing the preferences in Photoshop for the clipping points and the RGB values of the three eyedroppers. We usually set the white level at 253 and the black at 5 to avoid blocked up tonalities when using the auto tools. |
 Black, White, Gray Points Histogram |
For this approach we set a point in the image with the eyedropper tool where we wish the black and white values to be. Then keeping an eye on the info panel we shift the end points to bring these to the desired values. In our case, white about 253 and black about 5. We can observe the effect on the image as we make the adjustments. The steep curve shown here will make a much more contrasty image that the prior techniques. We are doing this for aesthetic reasons. |
 Manually Set Curves |
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the adjustment shown above will fix the contrast it doesn't
address the color balance. So we apply a second set of
curves. By setting markers on the row of gray squares along the bottom of the card we can make adjustments at each gray level to neutralize the color balance. This is more exact that just using one point as is done with the gray eyedropper. Here is the blue curve. |
 Blue Curve |
| Here
is the green curve. The deviations from a straight line are much
smaller. |
 Green Curve |
| Here
is the red curve. Notice the upward adjustment in the darkest
tones. This type of adjustment can also be done to control specific colors that don't reproduce properly. |
 Red Curve |
This is the final image after the contrast and color balance curves have been applied. There are a full range of tonalities shown, the gray patches are all neutral and the colors have been given a lot of "punch". There are still some color reproduction problems, specifically the yellowish square that is in the second row and is second from the right should be yellow green. This may be a failure of the film to capture the colors correctly or a problem with the profile used to characterize the scanner. So there are still some judgments to be make in the choice of film! Even so, we now have a way to capture all the tonality in the negative. This is a big improvement over the solutions shown using only the Minolta supplied software. |
 Final Image |
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© 2003 Robert D Feinman
