Re: Grain aliasing: do some neg films suffer less than others?

["Alan Rew" <arew@xxxxxxxxxxxxxxxxxx>]

----- Original Message -----
From: Ralf Schmode <rschmode@gmx.net>
To: <scan@leben.com>
Sent: Wednesday, April 03, 2002 1:55 PM
Subject: Re: Grain aliasing: do some neg films suffer less than others?


> [Nikon Scan Shadow clipping]
>
<snip>
>
> let me clarify a bit: I have space at both ends of the histogram, too,
with
> Nikon Scan but on the left (shadow) side of negative scans the "hump"
of the
> histogram ends abruptly rather than gradually. So, the shadows aren't
clipped
> in the sense of them being all black but clipped in the sense of
lacking
> definition in the darkest area of the negative scans (changing analog
gain
> doesn't help, by the way).

Ralf,

I've just looked at histograms for previous scans from my Canon FS2710,
and they too have this 'abrupt end' feature, for both negs and slides.
So the Nikon LS40 appears to be very similar to the Canon in this
respect.

With neither scanner have I seen any problems in the scans such as
posterisation or other nasty surprises, certainly they're no worse than
photo prints I've had done in the past.

As I've never used a high-end film scanner such as one of the Flextights
or a drum scanner I've no idea whether they would produce a histogram
that's any different in terms of the 'abrupt end' phenomenon you're
concerned about. It might be worth starting a separate thread on this
subject and see whether anyone has seen similar results on better
scanners.

If you contact me off-list I can send you some histogram screen shot
GIFs of my Canon neg and slide scans, to compare with your Nikon
results.

> Vuescan's ICE is a bit poorer as to dust removal than Nikon's
implemetation
> but it does create a better "overall" balance than Nikon Scan. "medium
> ICE/light GEM" is my choice for negs, "light ICE/light GEM" is for
slides.

Thanks for these settings, I'll try them. Since having <any> dust
removal done for free is still a novelty to me, I'm not too worried at
the moment as to whether VueScan is as good as Nikon Scan or not.

> > Yes, I can confirm that the colour accuracy from VueScan with the
Nikon
> > is just as woeful as it was with the Canon.
>
> You can create a macro (or "action" in Photoshop) that will take care
of
> Vuescan's "typical" color casts, especially the magenta highlights.

Interesting that VueScan produces 'typical' colour casts. If it's
consistent then it should be possible to calibrate it in some way.

> By the way,
> the better setting for slides is "image", not "35 mm slide". I use
"auto
> levels" white balance for both negs and slides.

Thanks for these tips. It seems that VueScan settings aren't as obvious
as I was hoping!

> > I've tried telling VS to use various profiles for the destination,
such
> > as Adobe RGB and Wide Gamut RGB, but with no apparent benefits. To
be
> > fair, I should start a separate thread on the Colour Management
issues.
> > My main concern at present is the <grain> issue.

> Having found out that most of those profile settings in Vuescan are
good for
> nothing, my approach has become different: I don't care about VS color
casts
> any more but let it give me the scan with all its weaknesses, and do
the
> tweaking in Picture Publisher, 95% of it with a gamma curve that has
seven fixed
> points across the tonal range of each color channel.

Well, that's one way to do it. I've got a lot of experience adjusting
colours from my Canon anyway, so this wouldn't be much additional
hardship.

As someone who uses conventional ICC colour management elsewhere in my
system, I'd still like to crack the issue of colours from VueScan via
that method, but the fact that you've had success with some standard
curves is very useful information in itself and gives me another way of
attacking the problem.

Regards,

Alan Rew


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