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Revision Date: 15 January 2023

Blur Effects

This sub-menu contains seven blur effects which are used to blur sections of an image.

Blur Effects
Blur Effects

Note

Looking for Unfocus? In Paint.NET 5.0 the Bokeh effect has replaced Unfocus (Bokeh even shows the same icon Unfocus used to have).  Bokeh is able to replicate the transformation Unfocus used to produce, while allowing finer control of the effect via the Radius, Gamma and Quality controls.

The following image will be used to demonstrate the Blur 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 Blurs Bokeh icon Bokeh

Applies the BOKEH effect to the source image.
Bokeh is most commonly seen as the blurred effect in the out-of-focus portion of a photograph taken with a narrow depth of field. Applying the effect to parts of an image draws the viewer's attention to the unblurred subject.

The Radius defines the effect strength or amount of blurring.
Gamma: Pre-set options in the dropdown list are sRGB (2.2), Linear (1.0) and Custom. Note: any change of the Gamma Exponent slider will change the list option to Custom. Pushing the gamma up has a "high key" effect where lighter tones start to dominate, while there is an apparent reduction in overall contrast. Dropping the gamma has a "low key" effect where darker tones get darker and contrast appears to increase.
Quality: can be thought of as a fine-tuning of the blurring. Low Quality will reveal slightly more detail while a high Quality will soften detail.

Example - Effects > Blurs > Bokeh

Effects > Blurs > Bokeh

Effects Blurs Fragment icon Fragment

Copies or "fragments" of the image are superimposed over the original.  The specified number of copies (Fragment Count) are redrawn at a Distance and Rotation to the original location as specified in the dialog.

This blur can be useful when creating an unfocussed multi-viewed version of an image. The effect is not unlike modern interpretations of insect-like vision and could be used to fake "drunken" or "semi-conscious" vision.

Example - Effects > Blurs > Fragment

Effects > Blurs > Fragment

Effects Blurs Gaussian Blur icon Gaussian Blur

This blur applies the well known Gaussian blur formula to the image. The result is a defocusing blur in it's simplest sense.

Radius. This a measure of how strong the effect is.
Gamma: Pre-set options in the dropdown list are sRGB (2.2), Linear (1.0) and Custom. Note: any change of the Gamma Exponent slider will change the list option to Custom. Pushing the gamma up has a "high key" effect where lighter tones start to dominate, while there is an apparent reduction in overall contrast. Dropping the gamma has a "low key" effect where darker tones get darker and contrast appears to increase.
Quality: can be thought of as a fine-tuning of the blurring. Low Quality will reveal slightly more detail while a high Quality will soften detail.

Example - Effects > Blurs > Gaussian Blur

Effects > Blurs > Gaussian Blur

Effects Blurs Motion Blur icon Motion Blur

This effect is useful for adding an illusion of motion to an image, as if a photograph had been taken while the subject was moving across the frame.

The Angle of apparent motion is configurable as is the Distance, which is a measure of how far the effect shifts the original pixels.
The Centered checkbox when checked will apply the blur from the center outwards.
Edge Behavior: Options are Clamp, Wrap, Mirror and Transparent. These dictate what will happen if the blurring extends off the edge of the layer.

Example - Effects > Blurs > Motion Blur

Effects > Blurs > Motion Blur

Effects Blurs Radial Blur icon Radial Blur

This effect is similar to Motion Blur, except that the apparent movement is along a circular path instead of a linear path.

The Center shows where the effect will be interpreted from. Center is relocatable: use the double slider control or drag the cross hair in the thumbnail preview.
Quality changes the output. Low Quality is useful for previews, small images or small angle values. High quality is slower to render and is better used for final images, large images or large angles.

Example - Effects > Blurs > Radial Blur

Effects > Blurs > Radial Blur

Effects Blurs Surface Blur icon Surface Blur

This effect is used to reduce soft details or noise in an image while retaining most edge details and contrast. The result is a cleaner, simplified version of the original.

The Radius value determines the sample size. Larger samples will usually produce fewer details.
Threshold acts as a tolerance level. Low values will yield finer detail while higher values will lose more detail.

Example - Effects > Blurs > Surface Blur

Effects > Blurs > Surface Blur

Effects Blurs Zoom Blur icon Zoom Blur

This effect gives the appearance of motion towards the image subject. The effect effectively mimics blurring in the 3rd dimension as if the viewer was rapidly closing in on the focal point.  Another way of looking at this effect is that it is Motion Blur applied outwards from a central point.

Distance determines how far the blurring will extend.

Focus is a measure of how sharp or diffuse the blurring will be.

The Center shows where the effect will be interpreted from. Center is relocatable: use the double slider control or drag the cross hair in the thumbnail preview.
Quality changes the output quality. Low Quality is useful for previews and small images. High quality is slower to render and is better used for final images or large images.

Example - Effects > Blurs > Zoom Blur

Effects > Blurs > Zoom Blur