

Technically, it works by modifying the layer’s alpha channel, which controls the transparency of the layer. I’ll also include a couple of handy tips for making the masking process much easier! How Does Masking Work?Ī mask is a kind of invisible secondary layer that sits over the top of a standard pixel layer, controlling which areas of the underlying pixel layer are visible. But if you’re new to the world of masking and you want to understand how they work in more detail, then read on. If you’ve already used masking in a different editing program, that’s probably all you need to get going on your project in GIMP.

Step 3: Click the layer mask thumbnail in the Layers panel to make it active, and use the Paintbrush tool to paint black and/or white pixels on your layer mask.

