Adobe Photoshop CS5 for Photographers - Martin Evening [209]
3.
Now comes the clever part. I could tell from the current state of the layer mask that while the body outline was looking good, the biggest problem was (as always) how to most effectively mask the hair. In this screen shot the Refine Mask dialog was set to the Reveal Layer ( ) preview mode. Here, I selected the refine radius brush (circled) and started brushing over the outline of the hair. There are a couple of things to point out here. By working in the Reveal Layer preview mode, you can see more accurately where you are brushing, as the green overlay allows you to see which areas have been selected. You won't actually see the results of this masking refinement yet, but it helps using this preview mode in the initial stages. The second point is that the Refine Mask recalculates the mask edge after each single brush stroke, so you can't expect to apply a quick succession of brush strokes to define the mask, instead you do so by applying one brush stroke at a time. You'll also notice how Photoshop pauses for a few seconds while it carries out these calculations before it allows you to continue.
4.
To refine the mask further, it was now best to revert to the ‘On Layers’ ( ) preview option as this allowed me to preview the mask edges against a transparent backdrop. At this stage I continued to work with the refine radius brush to perfect the edges of the hair outline. One can use the key to select the erase refinement tool ( ) and remove parts of the mask, but in this instance I found that the refine radius brush was the only one that was needed here. As in the previous step, you have to apply a brush stroke and then wait a few seconds for Photoshop to recalculate before applying any further brush strokes. I then adjusted the Shift Edge slider to contract the mask edge slightly and make it shrink more to Angelica's outline.
5.
It was all very well looking at the masked image against a transparent background, but the real challenge was how the image previewed against backdrops of different color and lightness. To test this particular masked image, I selected the ‘On White’ ( ) preview. By previewing the image against black I was able to get a better indication of how effective the mask was at separating the subject from the original background. As expected, I needed to check the Decontaminate Colors box in the Output section (circled) if the subject edges were to blend more convincingly with the white backdrop. As you can see, the mask was working quite well by this stage. However, I didn't want to decontaminate the layer just yet, so I unchecked this option for now.
6.
The real test though was how the masked layer would look when placed against a different background image. In this final step I took an out-of-focus image and dragged it across to the main image and placed this newly added layer below the subject layer. I then reselected the masked layer, and making sure the layer mask was active, I opened the Refine Mask once more. Now, since the mask edges had already been modified, I did not want to refine them any further, so I therefore set all the settings to zero. I did though want to now check the ‘Decontaminate Colors’ option in the Output section at the bottom. Now that I was able to preview the masked layer against the final backdrop I could tell how much to adjust the Amount slider. When I was happy with the way things were looking, I clicked OK to apply this final modification to the mask with the ‘New Layer with Layer Mask’ option selected in the Output To menu at the bottom of the dialog.