2.3. Gaussian Blur

2.3. Gaussian Blur
	2. Blur Filters

2.3.1. Overview

Figure 17.9. Example for the “Gaussian Blur” filter

Original

Blur applied

The IIR Gaussian Blur plug-in acts on each pixel of the active layer or selection, setting its Value to the average of all pixel Values present in a radius defined in the dialog. A higher Value will produce a higher amount of blur. The blur can be set to act in one direction more than the other by clicking the Chain Button so that it is broken, and altering the radius. GIMP supports two implementations of Gaussian Blur: IIR G.B. and RLE G.B. They both produce the same results, but each one can be faster in some cases.

2.3.2. Activate the filter

You can find this filter in the image menu under Filters → Blur → Gaussian Blur…

2.3.3. Options

Figure 17.10. “Gaussian” filter parameters settings

Blur Radius

Here you can set the blur intensity. By altering the ratio of horizontal to vertical blur, you can give the effect of a motion blur. You can choose the unit with the drop list.

Blur Method

IIR: IIR stands for “infinite impulse response”. This blur works best for large radius values and for images which are not computer generated.
RLE: RLE stands for “run-length encoding”. RLE Gaussian Blur is best used on computer-generated images or those with large areas of constant intensity.