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Revision Date: 10 January 2016

Noise Effects

This sub-menu contains effects that add or remove digital "noise".

Median is included in this sub-menu as it can be used to reduce noise at low settings. At higher settings Median acts like a blur.

Noise Effects
Noise Effects

The following original image will be used to demonstrate the effects:

Original Image
Original Image

Note

The examples on this page show the effects being applied to an entire image. It is easy to restrict the adjustment to a sub-section of the image simply by making a selection.  If a selection is active when the effect is run, it will only be applied to the selected region. Areas outside of the active selection will remain unchanged.

Tip

The controls shown in the effect dialogs operate in much the same way; drag the indicator left, right or in a circular motion (for an angle control).  Typing in a numeric value in the text box or using the up/down arrows beside the text box also changes the current value.  The keyboard arrow keys can be used to alter the value of a control once it has the focus.
Multiple controls can be used in isolation or combination. If more than one is altered, the cumulative effect will be shown.

Effects Noise Add Noise icon Add Noise

This adds random noise to the active layer or selection.

The effect must be run over areas containing color to produce noise. Running the effect over transparent areas produces no noise in that region.

Intensity determines how different the palette will be from the original. Low settings render the noise with a subtle or sympathetic palette, high values render the noise in garish colors less like the original palette.

Color Saturation is intensity of the coloring. At low settings the noise is rendered in monochrome (black and white). At high settings much stronger colors are seen.

Coverage dictates how much of the original will be covered by the effect. Higher values cover more of the selection or layer.

Example - Effects > Noise > Add Noise

Effects > Noise > Add Noise

Effects Noise Median icon Median

Radius specifies how much of the image will be sampled. At low Radius settings this effect can be used to remove noise and will render more detail.  At higher Radius settings it creates a blurring effect, rendering less detail.

Percentile is easiest explained as the amount of difference neighboring pixels need to exhibit to be retained. A low setting recovers more of the original detail.  A high setting removes more detail.

Example - Effects > Noise > Median

Effects > Noise > Median

Effects Noise Reduce Noise icon Reduce Noise

This effect is used to reduce digital noise in photographs. This noise generally occurs when digital cameras cannot correctly capture fine details or are produced by the electronics in the camera itself.

Radius specifies how much of the image will be sampled. Low values sample small areas while larger values increase the size of the sample.  The sample size dictates how many pixels will be compared to see if the pixel in question is similar enough to be considered noise or not.

Strength sets the power of the effect. Larger values will remove more noise and can also have a subtle brightening effect.

Example - Effects > Noise > Reduce Noise

Effects > Noise > Reduce Noise

In this example there is little ambient noise. The difference can be seen in the woodwork detail which looks cleaner after the effect has been run.