Photoshop: Layers - things you did not know

To duplicate a layer press command-J. Another quick way to do it is to press V (activate move tool), and then alt-drag the layer.

To copy part of a picture onto a new layer: select that part and press command-J.

To find out which layer contains a visible part of an image: command click on the image. The layer will be highlighted in the layer palette.

To display one layer at the time: alt-click on the eye-icon.

To fill the current layer with the foreground colour: press alt-delete. To fill the current layer with the background colour: press command-delete.

To load layer transparency as a selection: command-click the thumbnail.

To quickly change Blending modes: press V (activate move tool) and then press shift+(plus) or shift+(minus). For the each of the blending modes, there are shortcuts beginning with shift-option, like shift-option-F for Soft Light or shift-option-M for Multiply. They can all be found in the manual under the title "Keys for working with blending modes".

To change opacity: press V (activate move tool) and then type a number. 1=10%, 2=20% and so on. You can also change some of these methods.

To merge all visible layers to a new layer above the currently selected layer: Shift-option-command-E (or alt+ Layer > Merge Visible). This can be useful if you have smart objects, whose pixels you cannot edit directly.

To create a new layer from another image: drag the other image to the current one. To make sure it is centred hold down the shift-key as you drag.