7. The Menus / 7.7 The Filter Menu

7.7.16 Blur/Variable Blur

Variable Blur is a specialized Version of the Gaussian Blur. While the Gaussian Blur applies the same filter radius to the whole image, the Variable Blur adjusts the radius based on the mask value (see chapter 2.4.1) at the current location. This can be used to simulate depth of field.

A mask value of 0 means a radius of 0. There is no filtering. A mask value of 255 means maximum filtering: the value entered in the dialog will be used. The calculation of the values in between depends on Bias. If the bias value is 0.50, the radius will be interpolated linearly.

Please note, that you shouldn't use Variable Blur, if you don't have a soft mask with values between 0 and 255. If you don't have a soft mask, Variable Blur is just a very slow Gaussian Blur.