[filmscanners] Re: Scanning a foggy image

["Julian Robinson" <jrobinso@pcug.org.au>]

Brian,

A slightly different view for you to take into account on your weekend
experiments.

IME "atmospheric" and "foggy" mean pleasing low contrast, hi key
shots.  One of the things that annoys me  most about my LS2000 and
NikonScan is its overly aggressive auto exposure which seems to cut off
high and low levels and stretch what remains to fill up the entire
brightness range.  This is fine in normal circumstances when the contrast
range on the slide is more than the scanner can handle, but is not fine for
flat low contrast scenes like yours.

IN your case the autoexposure would result in a high contrast version which
would look nothing like the original, with exaggerated noise as well as the
higher overall contrast.  Now, in the LS2000 version of Nikonscan 3, there
is a nifty control called "low contrast" which I use all the time. In fact
it gives you options for high key, lo key or neutral, so the setting of
"low contrast high key" would be the go for your slide.

Unfortunately AFAIK from discussions on this list and with Nikon, this
feature does not exist in the same software when used with the LS4000 and
8000.  I have not been able to discover whether this is because Nikon
believe they have better software/hardware solution to the problem in the
newer scanners and so this facility is not required, or whether it is a
useful feature that just got lost between the cracks somewhere.  All I know
is it is not available with the newer scanners, and I could not use
Nikonscan on the LS2000 without it.

Assuming I am correct and the LS4000 does not have this available, your
options as I see it are:

1) scan it normally, and reduce the contrast in Photoshop or whatever you
use.  This has the disadvantage that you can't recover any info truncated
by scanner at top and bottom ends of the histogram, if significant. On the
whole I think this is likely to work well.  Why don't you post a jpg of
your scan so others can have a go at "fixing" it?

2) "fool" the auto-exposure by inserting a normal contrast slide and
autoexpose on that, then remove and scan your misty slide without resetting
exposure.  You might have to experiment with different "normal" slides for
exposure setting till you get the effect you want.

3) there may be another contrast management tool I don't know about on the
LS4000, or a means of manipulating exposure.

So long as you get all the information into your histogram, I don't think
it matters what it looks like off the scanner, because you can compress it
or do whatever to your heart's content in Photoshop.

Julian


At 04:09 06/08/02, you wrote:
>Fog isn't noise, it's a reduction in contrast due to adding a certain amount
>of diffused light on top of the rest of the image. The only way I can
>imagine a scanner reducing fog would be if it increased the contrast. You
>may be able to get it back by opening Curves and lifting the bottom left end
>of the curve up a bit.
>
>Another possibility is that the monitor isn't calibrated quite right, and
>it's chopping off the darkest end of the scale, thus increasing the
>contrast.
>
>--
>
>Ciao,               Paul D. DeRocco
>Paul                mailto:pderocco@ix.netcom.com
>
> > From: Brian
> >
> >     OK, let me ask a question. I have a rather nice slide of a boat dock
> > with some small boats moored which I took up in Maine. There was a slight
> > fog/mist in the air when I took the shot. A print made from the slide
> > captures the foggy nature of the composition nicely. However,
> > when I scan it
> > (Nikon Coolscan 4000) using ViewScan, the scanner/software seems to
> > interpret the fog as noise(??) and produces a scan with more clarity than
> > the original image has.
> >     My question is, how do you scan slides or negatives which are somewhat
> > soft with fog or mist and retain the look of the original scene? Failing a
> > scanning solution, is there a tweak I can do in Photoshop to get the
> > appearance back? I've been doing this for about a year so I'm not real
> > experienced by I have learned quite a bit reading the emails on
> > this group.
>
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