Adobe Photoshop CS5 for Photographers - Martin Evening [203]
Figure 9.17 In this next panel screen shot, the border surrounding the vector mask indicates that the vector mask is active and that any editing operations will be carried out on the vector mask. In this example, the image layer, layer mask and vector mask are now all linked. This means that if the image layer is targeted and you use the move tool to move it, the image layer and layer masks will move in unison.
The most important thing to remember about masking in Photoshop is that whenever you apply a mask you are not deleting anything; you are only hiding the contents. By using a mask to hide rather than to erase unwanted image areas you can go back and edit the mask at a later date. If you make a mistake when editing a layer mask, it is easy enough to correct such mistakes since you are not limited to a single level of undo. To show or hide the layer contents, first make sure the layer mask is active. Select the paintbrush tool and paint with black to hide the layer contents and paint with white to reveal. To add a layer mask based on a selection, highlight the layer, make the selection active and click on the Add Layer Mask button at the bottom of the Layers panel, or choose Layer Layer Mask Reveal Selection. To add a layer mask to a layer with the area within the selection hidden, -click the Layer Mask button in the Layers panel, or choose Layer Layer Mask Hide Selection.
Lastly, the mask linking buttons referred to in Figures 9.16 and 9.17 allow you to lock or unlock a mask so that you can move the mask or layer contents independently of each other.
Copying a layer mask
You can use the key to drag/ copy a layer mask across to another layer.
Viewing in Mask or Rubylith mode
The layer mask icon preview provides you with a rough indication of how the mask looks, but if you -click the layer mask icon the image window view switches to display a full image view of the mask (see Step 1 opposite). If you -click the layer mask icon, the layer mask is displayed as a quick mask type transparent overlay (see Step 2 opposite). Both these steps can be toggled.
Removing a layer mask
To remove a layer mask, select the mask in the Layers panel and click on the Layers panel Delete button (or drag the layer mask to the Delete button). A dialog box then appears asking if you want to ‘Apply mask to layer before removing’ (Figure 9.18)? There are several options here: if you simply want to delete the layer mask, then select ‘Delete’. If you wish to remove the layer mask and at the same time apply the mask to the layer, choose ‘Apply’. Or click ‘Cancel’ to cancel the whole operation.
Figure 9.18 The remove layer mask options.
To temporarily disable a layer mask, choose Layer Layer Mask Disable, and to reverse this, choose Layer Layer Mask Enable. You can also -click a mask icon to temporarily disable the layer mask (when a layer mask is disabled it will appear overlaid with a red cross). A simple click then restores the layer mask again (but to restore a vector mask you will have to -click again). Or alternatively, right mouse-click the mask icon to open the full list of contextual menu options to disable, delete or apply a layer mask (see Figure 9.19).
Figure 9.19 The layer mask contextual menu options.
Adding an empty image layer mask
If you create an empty layer mask (one that is filled with white) on a layer, you can hide pixels in a layer filling or painting with black. To add a layer mask to a layer with all the layer remaining visible, click the Layer Mask button in the Layers panel (Figure 9.20). Alternatively, choose Layer Add Layer Mask Reveal All. To add a layer mask to a layer that hides all the pixels, -click the Add Layer Mask button in the Layers panel. Alternatively, choose Layer Add Layer Mask Hide All. This also adds a layer mask filled with black.
Figure 9.20 Click the Add Layer Mask button to add a layer mask where the contents remain visible. -click to add a layer mask filled with black, where the contents are all hidden.