Re: Vuescan vs. Nikon Scan (was: filmscanners: Vuescan question)

[Rodrigo Amestica <ramestic@eso.org>]

Rob Geraghty wrote:
> 
> "Rodrigo Amestica" <ramestic@eso.org> wrote:
> > 1. after getting a preview, why does the GREEN histogram change when I
> > modify the RED gain (after pressing "redraw")?
> 
> Is it possible to adjust the gain of the colours separately?  I seem to
> recall Ed talking about different integration times for the different
> colours, but I didn't know there was a facility to adjust them individually
> in Nikonscan.
> 
> Rob

If you mean by colours the output of each red, green and blue channels
then the answer is Yes. You can adjust the Master, Red, Green and Blue
channels independently, and I guess that not only NikonScan but all the
film scanner software around provide such interface.

I thought that "analog gain" did mean a control on the intensity of the
light source, if instead of that it means a way to control the
integration time on that channel then the result should be more or less
equivalent.

I suppose that NikonScan (perhaps VueScan as well) recomputes the other
analog gains (intensity or int. time, whatever) after anyone of them is
changed. The problem is how to come to understand the way the software
does the re-calculation. 

Getting absolute command of analog gains is interesting for me because
the B&W usage I give to my system. Without much success yet I use to
scan RGB files from B&W negative film setting the gains something like
this:

red = 0
green = +2 stop
blue = -1 stop

So far, the results are not good enough because the nature of the three
light sources seems to have different behavior on the film. Grain and
contrast are render differently by each light source.

Rodrigo