[sane-devel] Affordable film scanner supported by SANE

[Jonathan Buzzard]

andras@users.sourceforge.net said:
> Orange mask: at least with Coolscan2, this one is trivial: adjust the
> exposure times of the R, G, B channels so that the space between two
> frames comes out exactly white. If you then scan with these settings
> and invert, all colours will be correct, and you have used the scanner
> at its best -- you get the best possible noise performance out of it. 

Yes you can do it. Does it match up to what VueScan does, and the ease
with which it does it yet; not in the slightest.

> Multi-pass scanning: is this really a front-end issue? (Otherwise I'm
> the culprit here since it's not yet in Coolscan2.) 

It depends if the scanner supports it and not all do. The basic problem
is that the SANE standard has no standard way of passing the information
between frontend and backend on whether you want multipass scanning or
not.

> Faded negative correction should be done in GIMP really. Pity
> mainstream GIMP only supports 8bpp colour. 

Really? I would rather download a custom gamma table to the scanner,
and use it for the whole film. Whatever the built in stuff in VueScan
generally gives just as good if not better results as messing around
in FilmGimp for ages just by clicking a check box.

> The IR channel certainly helps, but it has also been reported that
> scanners with LED sources exaggerate defects and therefore need an IR
> channel only to remove what a scanner with a xenon light source
> wouldn't see anyway. I'm sure there is some truth to it, a decent
> xenon-based scanner can probably give you a cleaner scan from a
> (clean!) frame than any Coolscan ever could. Then again, if you keep
> your films in a puddle, there's nothing that can beat an IR channel. 

I would point out you can do everything IR does with the clone tool and
plenty of spare time. The IR channel does it rather more quickly, which
is handy when you have some old family negative that has an important
photograph on it and has had less than ideal storage for the last 20
years.

> I don't think there is any traffic on it right now -- I think I'm a
> subscriber and I haven't got a message for quite some time. 

Maybe, but often asking a question will generate traffic on an
otherwise quiet mailing list.

JAB.

-- 
Jonathan A. Buzzard                 Email: jonathan@buzzard.me.uk
Northumberland, United Kingdom.       Tel: +44(0)1661-832195