[filmscanners] RE: Scanner Exposure Settings

["Paul D. DeRocco" <pderocco@ix.netcom.com>]

> From: Bill Seramin
>
> What happens internal to the scanner when adjustments are made on the
> scan software?  In my mind I can only equate how a camera exposes film;
> adjust exposure time and aperture.  Now I am confident in assuming that
> the scanner does not have a variable mechanical aperture, an equivalent
> for shutter adjustment, and from what I can tell the lamp brightness
> does not vary during scanning.  So what happens when endpoints and
> curves are adjusted in the scan software?  Maybe I have dense film or a
> dense brain, but I am having trouble visualizing what is going on.

The only "hardware" variable is exposure time, which is how many
milliseconds it spends on each scan line before moving on to the next one. I
don't know about the Polaroid driver but in Nikon drivers this is labelled
Analog Gain. Everything else is done by arithmetic on the resulting numbers.

--

Ciao,               Paul D. DeRocco
Paul                mailto:pderocco@ix.netcom.com


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