How do I create a special brush that instead of drawing a colored line adds a black line outside automatically?
Hello @Hadil_Hadil, and welcome to the forum!
Maybe by asking our all-knowing forum search or a look into our resources’ category for Brushes & Bundles?
But this post of mine has perhaps all you need together:
Michelist
I normally use the Stroke feature within the Layer Styles for stuff like that. However, if you must have a brush that creates a void at its center, select the Pixel Engine (or a preset that uses it), set the main brush tip to be the shape you want. Now select a brush tip for the “Masked Brush” option and, at top of the brush editor, set the “Blend Mode” for the Masked Brush to use “Subtract”. This will basically make the secondary brush act as a cookie cutter, putting holes in the stroke the main brush tip makes. I’ve shown an example of this in the attached screenshot.