Unless the scanner has user-adjustable lamp-control, exposure adjustment is not a scanner dependent operation. It is software controlled.
Mark, I didnít reply this statement before because, although itís wrong, it seemed to be irrelevant, and I didnít see any reason to debate a point neither I nor Herbert raised. But on reflection, maybe there is some use in discussing it.
My scanner and scanning software (Minolta 5400) has an exposure adjustment. It works similar to camera exposure adjustment. It controls the scan time. The physical effect is very obvious. With increases or decreases in exposure the scan time can vary significantly.
I know that you also own a Minolta 5400. So I wondered why youíd make the false assertion about exposure adjustments. How could anyone who used that scanner not notice the very prominent control and the very obvious change in scan times?
Then it occurred to me that you mainly use SilverFast. Perhaps SilverFast doesnít implement the Minolta 5400ís exposure adjustment, so you werenít aware that it existed?
Iíve also used SilverFast with my scanner, but it has been a while. I recall that SilverFast could not access my scannerís manual focus controls, but Iím not sure about the hardware exposure control.
I found it a little frustrating that such expensive software that was a version specifically designed to operate my scanner couldnít access the manual focus control. I could have put up with that flaw, however, had I otherwise liked the results I got with SilverFasts, but I didnít. As a result, I havenít bothered to install it on my current system, so I canít check now to see if it also failed to implement the hardware exposure control. If so, however, it would explain why you werenít aware that some scanners (including a scanner you own) have hardware exposure controls that control the scan time.
In any event, my point is that if a scanner has an actual hardware exposure control, it would be better to optimize the hardware exposure rather than just rely on software exposure adjustments. The reason is the same reason that youíd want to optimize exposure in a camera rather than just rely on post processing.