self-assured digital photographers don't fear a bit of image noise.
Fortunately, anyone can find suitable noise filtering software, if
the relevant features of their camera won't do the job all right.
One of the most well known such applications is Neat Image, also available
as a plugin for Photoshop (and other widely used photo editing
programs). Albeit Photoshop's newer versions already contain
a noise filtering feature, Neat Image and similar dedicated tools
offer more settings, and likely a better and more accurate result.
Despite this statement, we still introduce the plugin now with
its simplified user interface.
installation, click Filter/Neat Image/Reduce Noise in Photoshop.
You'll have to load a photo first, of course. The application
window looks just the same as in the stand-alone version. Click Tools/Standard
Mode to switch to the simplified interface.
Image basically consists of two main components, activated by
clicking the tabs under the menu bar. Device Noise Profile attempts
to assess the profile for the camera used and the photo's noise level.
Simply put, it produces a map of noise layout and extent. The other
component, Noise Filter Settings, does the actual filtering
and lets you specify the relevant settings.
portrait of noise
are two easy ways to produce a noise profile. You can open a test
image done with an identical camera and film speed/sensitivity (Open
Test Image), or apply the plugin's Auto Profile feature
to a homogeneous area in the current photo. Both relevant buttons
are in the upper left corner of the window. You can also open a pre-defined
noise profile for your camera. Click Profile/Open, or the first
icon above the device info region in the upper right area. You can
download profiles free of charge for numerous brands and models from
fastest of the mentioned options is Auto Profile. Click the
button to have the application look for a homogeneous area in the
picture, and set up the noise profile based on it. You can also select
the area to use. You need to specify a homogeneous area of at least
64x64 pixels by dragging. If you fail to do so, a warning message
appears. After successfully drawing the box, click Auto Profile.
If you have taken more photographs with the same camera and
in similar circumstances that also need noise filtering, save the
profile by clicking Profile/Save As. This way, you won't need
to prepare profiles for those images, you can simply open the saved
next component can be invoked by clicking Noise Filter Settings.
Most of the options can be specified using the sliders on the right.
Above them, there are two icons again, this time in purple instead
of blue. The first is for loading previously saved settings, and the
second for saving the current ones. There are two Trash icons above
the sliders. These reset the controls to their default values. The
Preview and Apply buttons in the upper left corner are also
important. Preview shows the effect of the current noise filter
settings on a selected part of the picture. Simply click the button
to have the application select an area (the middle of the image).
You can also drag a selection rectangle in the picture. Make sure
to zoom the photo to at least 100% before using the preview
as it is needed to see noise and how well the removal works.
executes the noise removal on the whole picture, using the current
let's return to the sliders for now as the settings are not yet complete.
You can set the noise level relative to the predefined profile in
the Noise Levels region. That is, if you set both sliders to
0%, you specify a noise level exactly identical to the one in the
profile. Negative values indicate a lower noise level, while positive
values a higher one. Leave these sliders at 0% for now, you'll
still have the possibility to adjust them later.
of sliders, Luminance Channel specifies the noise level for
the luminance channel, while Chrominance Channel does the same
for the color channel(s). As you can see, they deal with the two most
important noise types, color and luminance noise. It is best to illustrate
how they work. The left side of the picture below shows luminance
noise, emphasized by sharpening. It can be observed in the form of
monochrome grains that can decrease the sharpness of the picture to
a significant extent. It is richly nourished by incorrectly executed
sharpening, which can turn a weak graininess into a raging ash-storm.
The right half of the picture shows color noise, a confetti torrent
of single or multicolored dots. It ruins color hues, especially when
backed by the strong noise filtering of digital cameras. It can also
be strengthened by increasing saturation.
have identified our two primary foes, color and luminance noise. The
sliders with the same names in the Noise Reduction Amounts
region can be used to specify their removal strength. Default values
are 60% and 100%. Use Preview to check the result
of filtering in the selected area. Click Apply to finalize
the procedure if you find the settings acceptable. If noise reduction
looks too mild, raise the Noise Levels sliders first, and only
increase Noise Reduction Amounts carefully afterwards, when
needed. Click into the preview rectangle to display the original noise
level so that you can compare it with the filtered result.
additional controls can be found below the sliders. They are also
for finalizing the image's appearance. Use Smooth Edges carefully
as it also blurs small details. Its usage should be avoided when working
with very detailed pictures (such as landscape photographs). Very
Low Freq helps in filtering coarse, low-frequency noise. The bottom
slider sets the extent of posterior sharpening on the luminance channel.
upper part of the following photo is the original, while the
lower one is the same piece filtered by Neat
time we'll look at Neat Image a little closer and get to know
its advanced interface.