Using Adobe Photoshop CS, Part 2 - Extract
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When we were talking about selections, way back in the beginning of this chapter, we mentioned how you can use tools such as the Magic Wand and the Magnetic Lasso to help make selections. Many times what you're trying to do is remove the background from a photograph (called silhouetting). Depending on the image, this could be a tedious task, and you may want to try using the Extract filter.
When you choose Filter, Extract, you'll be presented with another large dialog, with a large preview of your image in the center (see Figure 5.122). Select the Edge Highlighter tool to trace over the edge of the shape you're trying to silhouette. You can adjust the size of the brush, and the goal here is to have the actual edge you're tracing fall into the highlighted area. Make the brush big enough that you can easily trace the edge, but at the same time, don't make it so big that other elements are being highlighted as well (see Figure 5.123).
When you've highlighted the edge, switch to the Fill tool and click on the part of the image you want to keep. Whatever is not highlighted in your file will be removed by the Extract filter. Click on the Preview button to see what the results will look like (see Figure 5.124). Click OK when you're done.
Figure 5.122 The Extract dialog.
Figure 5.123 Tracing over the edge of your object with the Edge Highlighter tool.
Tip -In my experience, I've found that at times you want to manually silhouette an image (rather than use the Extract filter), because either the actual shape isn't good, or you want to enhance it. For example, if a person's hair is blowing in the wind and a few strands are flying in odd directions, you'll want to get rid of those strands, not keep them.
Figure 5.124 A preview of the object with the background extracted.
Liquify
Thinking back, one of the highlights of kindergarten for me was finger painting (hey, it wasn't that long ago). The cool squishy paint, the smell, and, most of all, the ability to mush around and mix the colors to create art worthy of nothing less than my mother's refrigerator door. Although Photoshop can't create bright orange handprints on your classmate's dress, the Liquify feature can come pretty close to adding fun to your day (and Mom will still hang it on the fridge).
Seriously, though, the Liquify filter can be quite useful by allowing you to smudge, pull, and distort your photos. Begin by choosing Filter, Liquify, and once again your entire screen will be filled with a dialog box (see Figure 5.125). Choose any of the liquify tools along the left of the dialog and change the brush size by using the bracket keys on your keyboard. Other options are available in the Tool Options section on the right side of the dialog, and there's an option to use your pressure-sensitive tablet as well (see Figure 5.126).
What's so great about this filter is that you can apply distortions to your file, but you can also reconstruct your image to reverse the effect of your distortions by using the Reconstruct tool. You can also use the Freeze Mask tool to highlight areas you don't want affected by the distortion tools. If you use the Liquify filter on a low-resolution image, you'll see real-time performance and you'll have a fun time distorting your image. But you won't be having as much fun on high-resolution images because applying distortions to them takes a lot of computing power.
Figure 5.125 The Liquify dialog.
Figure 5.126 Using the Liquify tools to apply distortions to your image.
If you've used Illustrator before, you may be familiar with something called "mesh." Used for gradients and envelopes, a mesh is a matrix of points used to describe a distortion (in it's most basic form). Photoshop incorporated this mesh concept behind the scenes with the Liquify filter in that as you use the tools to create your distortions, Photoshop saves all the information as a mesh. At home, you're thinking, "Um, glad to hear that-let's get on with the lesson already,"but what this allows you to do is save your distortion mesh from Photoshop and apply it to other files (see Figure 5.127).
Figure 5.127 The Load and Save Mesh buttons in the Liquify dialog.
Let's apply the concept to a real-world example. You are working with a low- resolution file in your comps, and then when you get client approval, you'll replace all of your files with high-resolution ones. You can save the mesh from your low-res file and then apply it to your high-res one. To save a mesh, click on the Save Mesh button in the Liquify dialog, and use the Load Mesh button to load one.
 This chapter is from Adobe Creative Suite, by Mordy Golding (Sams, 2003, ISBN: 0672325918). Check it out at your favorite bookstore today. Buy this book now.
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