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[filmscanners] RE: Digital ICE


  • To: lexa@www.lexa.ru
  • Subject: [filmscanners] RE: Digital ICE
  • From: "Jack Phipps" <JPhipps@asf.com>
  • Date: Fri, 8 Feb 2002 09:34:08 -0600
  • Unsubscribe: mailto:listserver@halftone.co.uk

Good morning Art!
You do bring up some interesting points.

>However, your comment brings another issue into question.  Are you
>saying that the older Nikon scanners automatically applied "electronic
>sharpening" (is that a type of electronic filtering?) which was beyond
>the true sharpness of the image, and that added sharpening artifacts?
>Does this mean we could not trust to get a non-sharpened image from some
>scanners, or was it necessary to go into a manual mode to remove this
>extra sharpening?

The process of scanning will soften an image compared to photographically
enlarging and printing an image. Nearly every scanner uses some electronic
or digital sharpening.

The amount of sharpening varies from scanner to scanner and the methods
employed vary as well. Sharpening always causes artifacts. One can determine
what kind and how much sharpening is applied by examining these artifact
signatures.

>If indeed some dyes (like some Kodachrome cyan dyes) and silver based
images
>are opaque or partially so to IR, then I assume some materials that "dirt"
can
>be made of, can also be IR opaque.  If so, I don't know how dICE can see
>"under" it.

You are right. When there are sever scratches and opaque material on the
film, Digital ICE will leave some artifacts. When there are surface
imperfections, translucent dust, fingerprints and other imperfections, the
scanner will see it and record it and Digital ICE will correct for it. And
many times, when there is opaque material on the surface of the film the
light is refracted around it. This information is used to correct the image
as well. We are constantly improving the product and finding better ways to
identify and correct defects.

I should remind you that I don't have as deep a photographic or technical
back ground as many on this list. I rely on our scientists and engineers for
my informtion. My mistake about TMAX comes to mind. I grabbed a roll of
Black and White film from my desk that we will be testing with our Digital
PIC technology. I thought it was chomogenic. But no, we plan on being able
to scan black and white film with our new technology (the one that scans
unprocessed film). I love to expose film, but I can't hold a candle to some
of the photographers on this list. I've spent some time in the dark room,
but nothing compared to many others. This technology is quite complex and
when I try to explain it without giving away trade secrets, and in a way
most can understand it, I may miss the mark. So don't hesitate to contact me
for further clarification. If I don't know the answer, I'll try to get you
one, if I can.

Thanks for your interest!

Jack Phipps
Applied Science Fiction

-----Original Message-----
From: Arthur Entlich [mailto:artistic-1@shaw.ca]
Sent: Thursday, February 07, 2002 2:30 AM
To: Jack Phipps
Subject: [filmscanners] Re: Digital ICE




Jack Phipps wrote:

> Hello Dan!
>
> The film version of Digital ICE never "replaces" pixels damaged by surface
> defects. That is how some of the other versions of infra red surface
defect
> software work. There are several programs out there that use infra red to
> identify surface defects. Digital ICE is unique (and patent protected) in
> that it "looks through" the surface defects and identifies the underlying
> information in the film. That is why Digital ICE doesn't work when there
is
> a hole in the negative. If you take a pin and punch a hole in a negative
or
> scratch deeply into the emulation of the film, the defect will be
identified
> but not repaired properly.
>

 > It will never remove detail such as a single hair across a model's
 > face thinking it is a scratch like many other software based defect
 > removal programs.
 >
 > It never copies adjacent pixels like some other programs.
 >

I stand corrected on several points here, although I have to admit some
confusion.  Some things are simply opaque to IR, like some types of
dirt.  I can see how surface defects such as fingerprints, abrasions,
even some types of non-emulsion scratches can be "seen through", but
clearly some materials are fully opaque to both white and IR light.  As
I understand IR imaging, it allows for detection of thermal reflection
and transmission characteristics.  If indeed some dyes (like some
Kodachrome cyan dyes) and silver based images are opaque or partially so
to IR, then I assume some materials that "dirt" can be made of, can also
be IR opaque.  If so, I don't know how dICE can see "under" it.

Further, I have seen IR scans from filmscanners with dICE or IR scanning
ability.  The image picks up a number of things.  They have a ghost
image of the film dyes, they show dirt and dust and some defects as
darker black spots, and they appear to also show what might be residual
silver grains that didn't get fully bleached out.

So, I guess I'm wondering how dICE sees "under" IR opaque items and gets
away without using any interpolation.

 > Digital ICE should not blur your image. There are two reasons why some
 > believe that Digital ICE softens images. First, in the original Nikon
 > scanners where Digital ICE was first introduced, Nikon used two
levels > of electronic sharpening. When Digital ICE was run in the "normal"
 > mode, there wasn't as much electronic sharpening applied. You could
 > apply additional sharpening using an image editor (and it came with
 > the typical artifacts associated with digital sharpening). Therefore,
 > when you compared the two images, the "non-ICEed" version APPEARED
 > sharper than the Digital ICE version. Apply some digital sharpening
 > and the images would have the same apparent sharpness.
 >
 > The second reason Digital ICE images APPEAR less sharp is because
with > many images the highest level of detail in an image is the surface
 > defects!
 > Remove the surface defects using Digital ICE and the image may appear
 > less sharp. Compare the actual pixels in the scan and you should find
 > a similar level of sharpness.
 >

Secondly, I stand corrected as to the matter of softening.  It was
rather obvious on the older Nikon's that the two scans (non-dICE versus
dICE) shown on websites and even in the Nikon ads, demonstrated more
soft results with the dICE applied.  There was an "apparent" improvement
with the newer Nikon scanners, which I now assume is due to the changes
in the sharpening filtration used.

However, your comment brings another issue into question.  Are you
saying that the older Nikon scanners automatically applied "electronic
sharpening" (is that a type of electronic filtering?) which was beyond
the true sharpness of the image, and that added sharpening artifacts?
Does this mean we could not trust to get a non-sharpened image from some
scanners, or was it necessary to go into a manual mode to remove this
extra sharpening?

The reason I'm questioning this issue is because it seems to throw
testing resolution of scanners to the wolves, if some are sneaking in
"electronic sharpening" in the "normal" mode.

I will agree with you that grain and perhaps defects tend to make people
think "sharper", because our eyes want to focus on something distinct.

Art



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