[filmscanners] Re: 3 year wait

["Anthony Atkielski" <anthony@atkielski.com>]

Wayne writes:

> You can have 16 bits but if the 16 bits only
> covers a narrow density range, you will not
> see all the dynamic range in the film.

Yes.  However, CCD response is fairly linear and can cover an enormous
range, so on lesser scanners it is probably not so much a narrow density
range as an excess of noise at the low end, or inadequate illumination at
the high end.  Ideally, your CCD is refrigerated (to reduce noise and allow
it to pull more shadow detail without noise hiding it), and your light
source is bright enough to saturate the CCD through clear film with a
nominal exposure, no more and no less.  I don't know how close current
scanners come to this.  Under the best possible conditions, you could get as
much as 17 stops of dynamic range, enough to completely use the nominal 16
bits of a so-called 4.8 scanner.

> Is the scanner density then the maximum
> light to dark range before clipping?

If the vendor is honest, yes.  If the vendor is just going by the number of
bits the scanner records in output, then the published density figures start
to look a lot more impressive.  Sixteen bits of output, even if the scanner
can't quite resolve the last 2-5 bits.

> On these slide, there is just not any more
> information beyond 2700 ppi (lens and technique
> limits), but there certainly is more shadow and
> highlight detail that is being clipped in the
> scanner.

What settings do you have for the scanner?

On the LS-2000, I do see a lot of shadow detail, but it can be really noisy.
There is considerably more shadow detail on the LS-8000ED, and it has less
noise.  On both scanners, though, if I do 12/14 bit scans and carefully
adjust in Photoshop, I can pull detail from the shadows that was not visible
on the slide, in some cases.

> Trying to archive a lot of old film is a lot
> of work.

Scanning anything is a lot of work.  I spend far more time scanning than
shooting film sometimes, and far more time adjusting the scans than creating
them as well.  (But don't suggest digital--I had the same problems with
that, and worse images to boot.)

> When the histogram hits both ends, I know I
> am missing information.

I've rarely seen slides hitting both ends of the histogram on either the
LS-2000 or the LS-8000ED.  I have both scanners set up to provide unmodified
scans (except for autoexposure).  Are you sure you don't have anything set
that would cause clipping?

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