Nikon LS-3500 - LS-3510 - Manual (Page 44)

5-12 Using The Macintosh Scanner Plugin
Software Reference for Scanners
analog controls is that they minimize data loss for large changes, such as
compensating for dense images or heavy color casts. In most cases, the digital
controls will afford plenty of control for the kind of minor adjustments that are
usually made. The two figures above show how the two types of control sets will
appear, dependent upon the state of the Digital/Analog radio button pair.
Adjusting these numbers will produce a change in the preview image on screen.
Digital Mode
The digital controls all have a range from -5 to +5 with a nominal value of 0.
All these controls alter the gamma in a LUT (Look Up Table) that follows the A/D
(analog to digital) conversion in the scanner. The gradation changes are minor but
noticeable, and will be simulated in the preview without re-scanning. Best results
will be achieved with the optional 12-bit board installed when using these controls.
Analog Mode
The analog controls have a range of 0 to +255 for the brightness (exposure),
and color balance controls, with a nominal value of 50, and -15 to +15 for the
contrast (black level) control, with a nominal value of 0. There are five Text edit
boxes controlling Exposure, Black level, and RGB color balance.
Adding to any value when scanning positives will shift the color in that
direction. When scanning negatives, adding to the value removes that color. You
can directly control Red, Green, and Blue gain settings from 20 to 120. The
numbers that you input affect the reference value that was determined at Prescan
Photometry. This reference will always be 50, so that the resulting change in
exposure when these controls are manipulated is calculated as follows:
• 25=25/50 = .5 = 50% - meaning an exposure decrease of 1 stop (in
photographic terminology).
• 50=50/50 = 1 = 100% - meaning no increase or decrease in exposure.
• 75=75/50 = 1.5 = 150% - meaning an exposure increase of 1/2 stop
• 100=100/50 = 2 = 200% - meaning an exposure increase of 1 stop.
You cannot shorten the exposure time to be less than the minimum exposure
determined by prescanning. This is very often ~40. You may also find that the
CCD can oversaturate on specular highlights when the exposure time is increased
beyond ~100. The best application of these controls is to greatly alter the densities
and color balance of a scan. For example, if an image is too green, the green
exposure for a color positive can be decreased. Another way to counteract the
overall green cast is to increase the Blue and Red exposures by equal amounts.
Equal amounts of Blue and Red are equivalent to the same amount of Magenta,
which is the complimentaryoor opposite color to Green and will neutralize it.
> Note When increasing the analog exposure for a Positive scan, the resulting image
or color will be lighter than before. When increasing the analog exposure for
a Negative scan, the resulting image or color will become darker.