The Layer dialog is the main interface to edit, modify and manage your layers. You can think of layers as a stack of slides or clothes on your body. Using layers, you can construct an image of several conceptual parts which can be manipulated without affecting any other part of the image. Layers are stacked on top of each other. The bottom layer is the background of the image and the components in the foreground of the image come above it.
The Layer dialog can be called in many ways :
from the toolbox-menu:
/ /from the image-menu:
/from an other dialog-menu:
/from the (default) shortcut: Ctrl+L.
Using the Layerdialog
Every layer appears in the dialog in form of a thumbnail. When an image has many layers as components then it appears like a list. The upper layer in the list is the first one visible and the lowest layer the last visible, the background. Above the list one can find characteristics related individually to each layer. Under the list one can find managements buttons for the layer list. A right-click in a layer thumbnail opens the layer menu.
Every layer is shown in the list with its own attributes. The
main attribute is the name of the layer itself. You can edit it
by a double-click on the name or the thumbnail of the layer. In
front of the thumbnail is an icon showing an eye
. By clicking on the eye, you toggle whether the layer is
visible or not. (Shift-clicking on the eye causes all
other to be temporarily hidden.) An
other icon showing a chain
enables to group layers for operations on multiples
layers (for example with the Move tool).
![]() |
Tip |
---|---|
In case of an animation layer GIF or MNG the name of the layer can be used to specify some parameters : Layer_name (delay in ms) (combination mode), for example Frame-1 (100 ms) (replace). The delay set the time during the layer is visible in the animation. The combination mode set if you combine with the previous layer or replace it: the two modes are (combine) or (replace). |
Above the layer list it's possible to specify some properties for the active layer. The active layer is the one highlighted in blue. The properties are : "Layer mode", "Keep transparency", and "Opacity".
Layer modes: The layer modes adjusts how the layer interact with the other layers. From the combo box you can access to all the mode provided by Gimp. The layer modes are full detailled in the Glossary.
Keep transparency: If you check this option the transparent areas of the layer will be keeped, this even if you have checked the Fill transparent areas option for the Bucket fill tool.
Opacity: By moving the slider you give less or more opacity to the layer. With a 0 opacity value the layer is transparent and full invisible. Don't mistake with the Layer mask (see chapter Layer mask) that sets the transparency pixel by pixel.
Under the layer list a set of buttons allows you to perform some basis operations on the layer list.
Edit layer attributs:
You can change here the name of the active layer in the list.
New layer:
You can create here a new layer. A dialog is opened where
you have to fill the Layer name,
perhaps change default Height and
Width choose the Layer fill
type which will be the new layer background.
Raise layer:
You can here put the layer up a level in the list. Press the
Shift key to move the layer to the top of
the list.
Lower layer:
You can here put the layer down a level in the list. Press the
Shift key to move the layer to the bottom of
the list.
![]() |
Tip |
---|---|
To move a layer at the bottom of the list, first give a transparency channel to the Backgrpund layer (also called Alpha channel). Right click on the Background layer and select Add Alpha channel in the menu. |
Duplicate layer:
You can create here a copy of the active layer. Name of new
layer is suffixed with a number.
Anchor layer:
When the active layer is a temporary layer (also called floating
selection) shown by this icon
,
this button anchors it in the previous active layer.
Delete layer :
You can here delete the active layer.
A transparency mask can be added to each layer, it's called Layer mask. A layer mask has the same size and same pixel number as the layer to which it is attached. Every pixel of the mask can then be coupled with a pixel at the same location in the layer. The mask is a set of pixels in graytone on a value scale from 0 to 255. The pixels with a value 0 are black and give a full transparency to the coupled pixel in the layer. The pixels with a value 255 are white and give a full opacity to the coupled pixel in the layer.
To create a layer mask start with a right click on the layer to call the context menu and select Add layer mask in the menu. If the menu item is grayed first select Add Alpha channel in the same menu. A dialog appears where you can initialize the content of the mask:
White: the mask has no effect, all layer pixels are full visible.
Black: the mask gives a full transparency to the layer which becomes invisible.
Layer's Alpha channel: the mask is initialized according to the content of layer Alpha channel. If the layer still contains transparency it's copied in the mask.
Selection : the mask is initialized according to pixel values found in the selection.
Grayscale copy of layer: the mask is initialized according to pixel values of the layer.
When the mask is created it appears as a thumbnail right to the layer thumbnail. By clicking alternatively on the layer and mask thumbnail you can enable one or other. The active itemis highlighted by a white border (which is not well visible around a white mask). To view mask content instead of its effect in image window, press Ctrl Alt and then on mask thumbnail. To return to normal view redo last operation.
![]() |
Caution |
---|---|
The layer mask acts like a transparency mask on a particular layer. Since you have many layers it becomes different from the image Alpha channel which represents transparency applied to the whole image. |