>It's built into the hardware. I think only the Nikons have it. The
>way it's described implies that this control changes the brightness
>of the LED light source.
Unfortunately this isn't what it actually does. The "analog gain" actually
changes the integration time ie. how long the CCD is exposed for. The longer
the exposure, the greater the "analog gain". The exposure controls of other
scanners probably do the same thing. AFAIK the only one which cannot be
adjusted manually is the Acer?
PS You can try changing the analog gain to a large value in Nikonscan and
you will see how it slows the scanner down.
Rob Geraghty email@example.com