What's masked in GIMP

Work with masks

What are masks?

GIMP masks geometric areas in the image to protect them against accidental editing or to select them for special editing.

Both are possible at the same time in the GIMP. Masks should therefore serve to define areas in the image on which the processing with GIMP is concentrated, i.e. on parts of the image.

Note | Masks are symbolized by a so-called running "ant trail". It is an animated dashed line that permanently surrounds the mask area, similar to a small group of ants.

What GIMP masks are there

The following functions are available as mask tools: rectangular, mask, elliptical mask, free selection, magic wand, select by color, magnetic scissors and, in some cases, the path tool with which you can create individual masks.

Basically, all of these tools mask areas of your graphic, but they differ in their mathematical or physical processes in how they do that. While the rectangular and elliptical masks work purely geometrically, the "Select by color" mask, for example, uses certain color values ​​of your image to create a mask.

Create masks in the image

For example, you can easily create the rectangular mask in your images with the GIMP by selecting the relevant tool from the GIMP toolbox and dragging an area in the image with the left mouse button, for example from top left to bottom right. Release the left mouse button as soon as the masked area is sufficient.

You can also use keyboard shortcuts such as Shift and Ctrl available to be able to combine different masks with one another.

Other masks such as the magic wand "searches" and creates the selection of the mask independently on the basis of mathematical processes. You only have to click on an exemplary image area so that the magic wand "recognizes" what it has to select for you.

Combine and connect masks

GIMP masks are so flexible that they can also be combined with other masks. You can add (enlarge) masks together, subtract them from each other (cut out areas from masks) or combine both together as an intersection.

By being able to combine the most varied of masks with one another, you get a complex masking in the image.

Protect and edit areas

Masks are used to select the processing. If you have filters like for example Colors - Desaturate apply to the mask, then the processing always affects the inside of the mask.

Areas that are outside of a mask are automatically excluded from processing, so they are protected from processing.

Reverse / invert masks

However, if you do not want to select the inside of the mask as the target for processing, you can also invert masks.

With the help of the key command Ctrl + I you can invert the masks fix, alternatively with the menu Selection - invert. You can recognize this very well by the surrounding ant trail, which then runs around the edge of the graphic.