16.8. Chalk

16.8.1. Overview

Figure 17.387. Example for the Chalk filter

Example for the “Chalk” filter

Original image

Example for the “Chalk” filter

Chalk applied


This filter creates a chalk drawing effect for the active layer.

It is derived from the Chalk script (FileCreateLogosChalk in the image window), which creates a logo from a text of your choice, for instance:

The Chalk logo

[Warning] Warning

The image will always be resized to the active layer's size.

16.8.2. Activate the filter

You can find this filter in the image window menu under FiltersAlpha to LogoChalk….

16.8.3. Options

Figure 17.388. Chalk option

“Chalk” option

Background color

The background color is the color of the blackboard you are drawing on with chalk, and of course it's black. When you click on the color button, the color selector pops up and you may select any other color.

16.8.4. Filter details

The Chalk filter

  1. applies a Gaussian blur to the layer, spreads the pixels, and ripples the layer horizontally and vertically,

  2. extracts edges using the Sobel edge detect filter, and

    [Note] Note

    Sometimes the sobel edge detect produces some garbage at the image sides.

  3. increases the luminosity level.

Unfortunately you cannot change the tool and filter options. But you may reproduce the process step by step using the methods listed above, varying the respective options. Then you just have to add a background layer filled with any color. That's all.