Adobe Photoshop CS5 for Photographers - Martin Evening [162]
Adjustment layer masks
As you have seen so far, adjustment layers are always accompanied by a pixel image mask. As with ordinary layers, these can be used to mask the adjustment layer contents. Whenever an adjustment layer is active, you can paint or fill the adjustment layer image mask using black to selectively hide an adjustment effect and paint or fill with white to reveal again. You can also keep editing an adjustment layer mask (painting with black or white) until you are happy with the way the mask is looking (see Figure 5.56).
Figure 5.56 This shows an example of a darkening adjustment layer applied to an image, but with a black to white gradient applied to the pixel layer mask to fade out the adjustment from the middle of the image downwards.‘Stalkers’ by The Wrong Size. Photograph: © Eric Richmond
Having the ability to edit an adjustment layer mask means you can apply such layer adjustments selectively. For example, although Photoshop has dodge and burn tools, and these were improved in Photoshop CS4, they are still not really suited for dodging and burning broad areas of a photograph. If you want to dodge or burn a photo in order to darken a sky or lighten someone's face, the best way to do this is by adding an adjustment layer, filling the mask with black and painting with white to selectively reveal the adjustment layer effect. This is not to say that the dodge and burn tools serve no use. Yes, they were much improved in Photoshop CS4, but they are just not ideal for this type of photographic retouching. Working with adjustment layers is by far the best way to shade or lighten portions of a photograph. You have the freedom to re-edit an adjustment layer, to make the adjustment lighter or darker, plus you can edit the layer mask to precisely control which areas of the image are affected by the adjustment.
Masks panel controls
The Masks panel (Figure 5.58) can be used to refine the mask or masks associated with a layer (such as an additional vector mask). Layer masking is a topic I'll be discussing more fully in Chapter 9, but because it is relevant to masking adjustment layers, I thought it best to briefly introduce the Masks panel features here first.
Figure 5.58 The Masks panel controls.
Adjustment layers are added to the layer stack with a pixel layer mask, so the default mode for the Masks panel shows the pixel mask mode options. If you click on the Vector Mask mode button next to it, you can add and edit a vector layer mask (see Step 4 on page 361). You can tell which mode is active because it will say ‘Pixel Mask’ or ‘Vector Mask’ at the top of the panel and the relevant mode button will have a stroked border.
The Density slider can be used to adjust the density of the mask. When you have a mask applied to a layer or adjustment layer, where the mask is filled with black, this hides the layer contents completely. However, if you reduce the Density, this lightens the black mask color and therefore allows you to soften the contrast of the mask. So, when Density is set to 50%, the black mask colors only apply a 50% opacity mask and the lighter mask colors are reduced proportionally.
The Feather slider can be used to soften the mask edges up to a 250 pixel radius. Beneath this though is the Mask Edge… button which opens the Refine Edge dialog (Figure 5.57). Here you'll find you have even greater control over the mask edges and softness as well as some new controls in Photoshop CS5 that are described more fully in Chapter 9.
Figure 5.57 This shows the Refine Edge dialog.
The Color Range button takes you to the Color Range dialog, which allows you to make selections based on color. This means that you can select colors to add to or subtract from a Color Range selection and see the results applied directly as a mask. Beneath this is the Invert button for reversing a masking effect. At the bottom of the panel are options that allow you to: