Revision Date: 27 October 2024

Blur Effects

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

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

 Bokeh Blur

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. The result averages color in the surrounding circular area. 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 Boost: Raising the gamma value has a "high key" effect where lighter tones start to dominate, while there is an apparent reduction in overall contrast. Lowering the gamma value 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 by controlling its precision. Higher values produce a better approximation of a true Bokeh effect, and will take longer to render. Low quality values will not look as good, but will render much faster.

 Fragment Blur

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.

 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 Boost: Raising the gamma value has a "high key" effect where lighter tones start to dominate, while there is an apparent reduction in overall contrast. Lowering the gamma value 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 values will not look as good, but will render faster.

 Median Blur

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 has a similar visual result as Gamma Boost does for the Gaussian Blur and Bokeh Blur effects. It specifies the brightness bias for colors pulled from the neighboring pixels: the default value of 50 chooses colors at the most common brightness within a pixel's neighborhood (defined by Radius). Lower values choose darker colors, and higher values choose brighter colors.

Quality: Can be thought of as a fine-tuning of the blurring by controlling its precision. Low quality values will render more quickly, but will not look as good and will result in a posterized apperance. This can be useful for quick previews and for artistic purposes.

 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.

 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.

 Sketch Blur

Sketch Blur is a new blur effect unique to Paint.NET. It was adapted from Andrey Akinshin's implementation of the P² Quantile Estimator algorithm, which is used to calculate an approximation of the median for a stream of values. You can think of this algorithm as taking a Monte Carlo approach to calculating a median.

The effect produces an artistic effect like a coarse-grained brush stroke painting.

Radius specifies how much of the image will be sampled. Using the "coarse-grained brush painting " simile, low Radius settings, will create an effect as painted with a smaller brush. Higher Radius settings mimic a larger brush which will naturally render less detail.

Percentile has a similar visual result as Gamma Boost does for the Gaussian Blur and Bokeh Blur effects. It specifies the brightness bias for colors pulled from the neighboring pixels: the default value of 50 chooses colors at the most common brightness within a pixel's neighborhood (defined by Radius). Lower values choose darker colors, and higher values choose brighter colors.

Smoothness: Can be thought of as a fine-tuning of the blurring by controlling how many iterations of the effect are rendered. Low values produce crisper, rougher detail while high values produce softer, smoother detail.

 Square Blur

This simple blur effect computes the average color of the surrounding square area. This effect could be considered a very high-performance, but very inaccurate approximation, of the Bokeh Blur effect (which averages out the surrounding circular area).

The Radius value determines the sample size. Larger samples will usually produce fewer details.
Gamma Boost: Raising the gamma value has a "high key" effect where lighter tones start to dominate, while there is an apparent reduction in overall contrast. Lowering the gamma value has a "low key" effect where darker tones get darker and contrast appears to increase.

 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.

 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.