GIMP Layers Explained

In any tutorial on how to use GIMP (or even Photoshop) you’re likely to come across layers. I talked a little bit about layers in my tutorial on using the clone stamp tool. I didn’t go into much detail there for the sake of keeping the tutorial simple. If you’re new to GIMP you’ll want to know what layers are all about so you can start to use them effectively.

Layers are like sheets of tracing paper. You can draw a little bit on one sheet, and a little bit on another and when you stack them up and flatten them all out you get a cohesive image. Remember the scene in Iron Man when Tony Stark is done drawing his blueprints for the first iron man suit? There’s a dramatic moment when he flattens a stack of papers to reveal how all of the pieces fit together as one suit of armor. When I saw that I thought “They’re Layers!” (I know… I’m a dork…)

First you’ve got to open the Layers Dialogue

A dialogue is a fancy name for a menu. It lets you keep track of the layers you’re using.

To open the Layers Dialogue go to Windows > Dockable Dialogues > Layers in the Main GIMP window.

To keep that dialogue handy you can dock the Layers Dialogue to your Toolbox window. To see how check this out: http://pareandfocus.com/index.htm/learn-gimp-fast/

Here’s how Layers work in a nutshell

If the top layer is completely opaque you see only the top. The Opacity Slider is set to 100% so this white layer is 100% opaque.

If it’s a bit transparent, like tracing paper, you can see the top layer and some of the layer below. The Opacity Slider is set to 50% so the white layer is 50% transparent letting the flower show through.

If the top layer is completely transparent you won’t see it at all. All you’ll see is the layer below. Since you can’t see transparency it’s shown on the layer icon as a checkerboard pattern.

When you add a new blank layer (by clicking the icon at the bottom of the Toolbox that looks like a piece of paper) you are given the option of either filling it with the foreground or background color,  or starting a  transparent layer (the option is called Transparency.)

The Opacity Slider on a Transparency layer will control the opacity of anything you add to this layer. Right now it’s set at 100% opacity but it’s still a transparent layer.

If you paint on that completely transparent layer or write on it with text it will look like those marks are made directly on the layer below. It looks like I drew this smiley face right on Background copy. The opacity of New Layer is set to 100% so the smiley face is completely opaque. If the opacity were set lower, the smiley face would blend into the flower more.

One of the biggest advantages of working with layers is that you can very easily change parts of your image with out effecting the whole thing. Since I didn’t make the smiley face directly on Background copy, I can easily move or change it without changing the rest of the image.  I can even delete it if I don’t like it. The layers that I do like are safe.

Every time you open an image, the default layer is called “Background“. I recommend automatically duplicating that layer by right clicking (two-finger tap on Mac) the layer and choosing Duplicate Layer. I almost never touch Background b/c I want to preserve the original photo, just in case.

This is just the beginning of layers. Next up will be Blend Modes and Masks.