The basics

SCANNER AND
CAMERA TECHNIQUES
48 ADVANCED PHOTOSHOP ELEMENTS 5.0 FOR DIGITAL PHOTOGRAPHERS
2.18 Noise Reduction technologies
Suitable for Elements – 4.0, 3.0, 2.0, 1.0 | Diffi culty level – Basic
As part of the process of scanning an image, visual errors are introduced into the fi le that
were not part of the original. This is true to varying degrees for both entry level and high end
scanners. The most noticeable of these errors is called noise and usually shows up in shadow or
highlight areas of the picture as brightly colored random pixels or speckles. Image noise can be
caused by a variety of factors including high speed fi lm grain (high ISO), under- or overexposed
negatives or slides, lighting conditions with brightness extremes, and image enlargement, as
well as the CCD sensor itself. At worst, high levels of noise within a picture cause the image to
appear unsharp and less detailed and have the potential to distract a viewer’s attention away
from the content of the image. To help correct or, more accurately, minimize the impact of noise
in our digital photographs scanner manufacturers like Kodak, Minolta,
Cameras and noise Nikon and Umax have banded together with software producer Applied
Science Fiction(www.asf.com) to include ASF’s Digital GEM product in
Scanners are not the only capture devices
that can introduce noise into a digital their scanning software. GEM reduces image noise and grain during the
photograph. The sensors in cameras can scanning process and should be used when standard scanner settings
suffer from the same problems as those
found in scanners.
produce noisy results.
Generally, noise is at its worst in photographs
taken with high ISO
(equivalent) settings or
when the shutter speed is
longer than one second.
To help remove the noise
in camera-captured
pictures ASF also produces
a plug-in version of their
GEM software that can be
activated via the Filter
menu in Elements. This
version of the software
provides a little more
control than that provided
as part of the scanner
driver as it allows separate
adjustments for highlight
and shadow noise as well
as a slider control to alter
the sharpness of the
picture.
Alternatively, Elements
versions 5.0 contains the
Reduce Noise fi lter (Editor:
Filter > Noise > Reduce
Noise). As with the GEM
plug-in the fi lter contains
several sliders that help
balance noise removal and
overall sharpness of the
processed picture.
Book resources at: www.adv-elements.com
Removing noise >> Using a technology
such as ASF’s Digital GEM feature whilst
scanning will reduce the appearance of
grain in your picture whilst maintaining the
sharpness and clarity of the photograph.
(a) Noise before Digital GEM.
(b) Noise after Digital GEM.
(c) Elements’ new Reduce Noise fi lter.