[filmscanners] Re: Need some tips on Vuescan

["Peder Skyt" <pesky@pc.dk>]

"Shunith Dutt" <shunith@vsnl.com> wrote on Wednesday, May 01, 2002 8:54
AM:

Please use the latest version of Vuescan.
Please study the "Vuescan User's Guide" (find it in the Help page).

>> Set preview resolution to something like 500 dpi.
>OK... but why?

At some (high) preview resolutions Vuescan seems to do some kind of
nearest-neighbour downscaling, resulting in a pixelated image. To
minimize this scaling "damamge", set the preview resolution so that the
preview scan matches roughly the size (in pixels) of your on-screen
preview. 500 dpi was just a guess - I use 675dpi (sometimes 900 dpi)
with Vuescan maximized on a 1280x960 screen.

Higher preview resolution also means more time before you seee the
preview, _every_ time you refresh the preview.


>OK... but how do i set the focus point?

Move the oscillating focus marker with your mouse. Or enter the numbers
by hand. By the way, I always set "Crop units" to "pixel": It is easier
to enter integer numbers, it gives me maximum control, and anyhow I
don't see much point in using real-life sizes when working with digital
images.

>measure focus points across the image like in NS?

I have never used NS, so don't know how it works. With Vuescan you can
measure at one point, then move it and measure again, etc etc. If I need
perfect focus, I preview, lock exposure,  move the focus point to
somewhere contrasty near where I want perfect focus, do a manual
auto-focus, a new preview, then some more previews with Device:Focus set
0.025 up & down... but most times the auto-focus value turns out to be
the best choice.


>>> Saved as 48Bit Tiff file....
>> No, don't save as 48 bit RGB; save as 16 bit Gray.
>One tip given here was to save as 16/48 bit RGB and then convert to B&W
is
>PS if i needed to...

It is a waste of space (if you can get Vuescan to produce acceptable end
results). I used to get some really weird/colored results when it was
set to anything but Gray; that "feature" seems to have been fixed now.

if you  don't like how Vuescan does the RGB-to-Gray conversion, then
scan to a raw file (with proper exposure) and use your image editor to
do the conversion.

/Peder Skyt

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