Working with Layers in the GIMP

Many images consist of a stack of two or more layers. An image is generally easier to manipulate when its elements are on different layers, allowing an individual element to be worked on without disturbing the other elements. A layer has four basic attributes:

• Active/inactive: You can only change the active layer.

• Opacity: An image is a stack of layers. Opacity is the degree to which you can see through a layer to the layer beneath it.

• Visible: A layer can be visible or invisible. You can't see an invisible layer at all. However, it's still there.

• Position: The location of the layer in the stack of layerstop, bottom, or somewhere in between.

To see layer information, click Dialogs and select Layers, which opens the window on the right. The dialog shows three layers in the image, with thumbnail images. Use this window to manipulate the attributes.

Highlight a layer to make it active (in this figure, the first layer). This does not mean you can see the layer. Other layers may be covering it up. However, in this figure, the active layer can be seen because it is on top.

The eye on the left means the layer is visible. If a layer is covering up the active layer, the toolbar tools affect the active layer, but you can't see what is happening. Click the eye to make the layer invisible, so you can see the active layer.

The box between the eye and the thumbnail is a link. When this box is clicked for two layers, they move together when moved with the move tool.

The background layer is the bottom image. It can't be moved. However, the two upper layers can. If you click the down arrow, the highlighted layer moves down one position. The up arrow moves it up one position.

The active layer can be acted upon by any of the toolbox tools. It can be moved using the move tool in the toolbox. It can be deleted. Any effects in the menus can be applied to it. Images can be pasted into it. It can be duplicated using the middle button on the bottom of the layers dialog.