If you have worked hard to get a particular image layer just right, you will not want anything to happen to it accidentally. Photoshop CS provides some clever locking mechanisms to help you with this.

 

You will notice four icons running across the layers palette preceded by the word Lock.

 

 

These icons can be used to lock (prevent action on) different image elements. The first icon (checkerboard) is the transparent pixel lock. The next icon (paint brush) is the image pixel lock. The third icon (crossed arrows) is the movement lock, and finally, the last icon (lock) will lock everything.

 

If you click the first lock icon on the left (the one with the checkerboard pattern) the transparent pixels in the selected layer will be locked. This means that any edits that you try to perform will not affect the transparent pixels. For example, if you try to paint over the layer, strokes will only appear over the places where there is image data, not the transparent areas. This can be a useful way of constraining your edits to the image data alone. When you apply a lock of this type, you will see a shaded lock icon appear in the selected layer.

 

 

If you select a layer and click the paint brush icon (just to the right of the checkerboard icon) all of the pixels in the image will be locked. You will not be able to edit transparent or non transparent pixels. As before, a shaded lock icon will appear in the selected layer.

 

If you select a layer and click the movement lock (crossed arrows icon) you will not be able to drag the layer around in your image window with the move tool. The layer will be fixed in position until the lock is removed. Once again, a shaded lock icon will appear in the selected layer.

 

Finally, if you select a layer and click the full lock icon (looks like a lock) all of the preceding elements will be locked. You will not be able to edit or move the selected layer. If you choose this lock option, a lock icon that is mostly light (very little shading) will appear in the selected layer indicating that the layer is fully locked.

 

  

 

To remove a lock from a layer, click the corresponding icon in the row of lock options (labelled Lock) above the list of layers. (The lock option corresponding to the selected layer will be highlighted with a white field).