Advice on Selections

There is no single technique that is perfect for making the ultimate selection. It is the situation that dictates the technique, not your comfort level. It is important to get comfortable with all of the methods discussed in this book so you can begin to unlock Photoshop's power.

Garbage Mattes

Garbage matte is a compositing term. It means using a simple matte to block out the complex noise or garbage in the image that would otherwise interfere with a more elaborate matte. In other words, we chop the object out and then refine it.

When making selections, move quickly but effectively. I don't imagine you have time to spend 30 minutes generating the perfect selection. By making a broad selection with the Lasso, Quick Selection, or Color Range method, you have less to worry about. Then start to refine things down inside the Quick Mask mode. Finish it off with some touchups and feathering using the Blur and Smudge tools or the Median and Gaussian Blur filters. You also may find the Minimum and Maximum filters useful for "choking" the matte.

Along the way, you can employ intermediate alpha channels so that you can save your selection. If you mess up, some quick painting of the matte will get you back on track. Most intermediate users try to make the entire selection in one step, but they soon realize that a good selection involves several short (and quick) steps. Don't try to do too much with one click. Use all the methods as needs arise, and you will be fine.

Look First

^ Always check your stock images to see if they contain an embedded path or channel. A path or channel can be converted into a selection by holding down the IX ( L ) key and clicking on it.

Paths and Channels

If a photo comes with a path or channel, use it. Many editors are so deadline-driven that they forget to check if someone has already created a channel or path. There are a few ways to handle embedded data; all of them are far quicker than starting from scratch. As they say, there's no need to reinvent the wheel. Always check your Channels palette for an included alpha channel and the Paths palette for an included path or clipping path.

If you have a path or clipping path, simply B-a+click click) on the path thumb nail in the Paths palette. Then switch over to the Channels palette and click on the Save Selection as Channel icon. If you'd like a softer edge, run a Gaussian Blur filter on the alpha channel.

If you have multiple paths or channels that you'd like to combine, load the first one by KX+clicking (^0+clicking) on the path/ channel thumbnail. To load additional items, use the same key combo, but add the ^S key. When you have loaded all the selections, click on the Save Selection as Channel icon. It is a good idea to throw away any unused alpha channels before saving for your NLE. Most systems do not correctly interpret multiple alpha channels.

Unlike layers, you cannot merge channels, but Photoshop does have two helpful techniques for this situation. The Load Selection command (Select>Load Selection) allows you to load the first channel, and then add the second one. This creates a new selection, which then must be saved as a channel. Let's try merging two alpha channels:

Step 1. Open the file Ch04_Additional.tif from the book's DVD-ROM.

Step 2. Open the Channels palette and view the two existing alpha channels.

Step 3. Choose Image>Calculations to launch the Calculations dialog.

Step 4. Set the Source 1 Channel to Alpha 1 and the Source 2 Channel to Alpha 2.

Step 5. Set the Blending mode Add, which will combine them together.

Step 6. Specify that you want the result to be a New Channel and click OK. The new "merged" alpha channel is created.


Source 1 Ch04. Additional-[iff : 1

<—<* 3

Layer; Background ; |

( Cancel )

Channel: Alpha 1 M Invert

fijjj? Preview

Source 2: Ch04.Additional.tiff

Layer: Background J 1

Channel; Alpha 2 !] _ Invert

Blending. Add : 1

Opacity: 100 % Offset. 0 Scale: 1 □ Mask...

Result; New Channel ;

While many nonlinear editing systems support Photoshop layers, it is still a good idea to save flattened files with alpha channels. A PICT or TARGA file with an embedded alpha channel gives predictable, consistent results. (Courtesy of the American Red Cross.)

The Best of Both Worlds

^ By saving your document as a layered TIFF file, most NLEs and compositing applications will read the file as "flat." However, you can open the file and make edits to layers and transparency, which will then update after you close and save.

Photoshop Secrets

Photoshop Secrets

Are You Frustrated Because Your Graphics Are Not Looking Professional? Have You Been Slaving Over Your Projects, But Find Yourself Not Getting What You Want From Your Generic Graphic Software? Well, youre about to learn some of the secrets and tips to enhance your images, photos and other projects that you are trying to create and make look professional.

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