Technical data

KNOW-HOW
What is the advantage of a film
scanner compared to a flatbed
scanner with illumination source?
The main difference between flatbed scan-
ners with illumination source and film scan-
ners is that in flatbed scanners, the film is
placed on a glass plate from where it is scan-
ned.
In film scanners, the light is transmitted
directly through the films. Since glass plates
have a negative effect in the imaging per-
formance of optical devices, the mere tech-
nical layout of film scanners offer a decisice
advantage compared to flatbed scanners.
Disturbing effects, like Newton rings or blur-
ring due to bent potos due to the heating of
the glass plate do not occur with film scan-
ners at all or only when scanning slides with
glass frames.
Another advantage of film scanners
is their optical density:
The main task of flatbed scanners is to scan
top-view photos, i.e. reflecting photos with
a very small density range. To render all
details of film material, an optical density up
to a value of 3 is required which is reached
by very good film scanners only. As a result
of an insufficient density range, the shadow
areas and areas with bright lights have little
contrast.
What resolution is required for a
beamer projection?
An average beamer may be able to project
as many pixel to a wall as an average TFT
monitor can display, namely 1024 x 768 pixel,
multiplying to some 800.000 pixel, not even
1 megapixel. Even a small picture slide scan-
ned with 2000 dpi provides as much as 5
megapixel. If the scan resolution is cut half
to 1000 dpi, the resulting image still has
about 1.2 megapixel, which is absolutely
sufficient for a beamer or a normal monitor.
basis. An infrared beam scans the surface of
the film. Usually, negatives or positives have
a smooth surface. The infrared beam will
detect valleys (scratches, grooves) and
mountains (dust grains, fingerprints, etc.) on
the surface. When such a valley or mountain
is detected, the corresponding software cor-
rects the respective spot with the information
of the pixels found in the vicinity of the faulty
spot.
Does the scratch removal method also
work with black and white films?
The automatic dust and scratch removal
system works with colour slides and negati-
ves exclusively. When scanning black/white
photos, the removal system must be swit-
ched off.
If you nevertheless leave the scratch
removal system active when scanning a
black/white film, a milky photo will be the
result where the rough outlines only of the
displayed motives are visible.
Does the scratch removal method also
work with Kodachrome films?
The ICE/MagicTouch dust and scratch re-
moval system works with Kodachromes in a
way that dust and scratches are corrected
effectively. A negative effect, however, is that
also parts of the photo where there is no dust
will be blurred. Therefore, the system should
be deactivated for Kodachromes. The reason
for the problems of the ICE/MagicTouch
method with Kodachromes is the silver con-
tent of the films. In principle, Kodachromes
are black/ white films which are coloured only
afterwards.
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