Lesson 12

Saving patterns, brushes, and alpha channels

First, take a look at the Clone Stamp tool on the toolbar (left). The Clone Stamp tool is similar to the Healing Brush tool...in fact, it is the forerunner of the Healing Brush tool, since it was used in earlier versions of Photoshop before the Healing Brush was introduced. With the Clone Stamp, as with the Healing Brush, you first select an area of the image as the source. When you start painting, your brush copies whatever was drawn in the spot that you designated as the source. This allows you to paint over blemishes and other obstructions.

The important thing to note with the Clone Stamp tool is that it has an item called "Aligned" in its menu bar. If you check "Aligned," then the spot designated as the source from which the copy is drawn will move along with your cursor, no matter how many times you click. Unchecking "Aligned" means that every time you let go of the mouse button and click again while drawing, the source point reverts back to its original position.

Now click on the other option, the Pattern Stamp tool. This tool doesn't use part of the image as its source. Instead, it draws from the menu of saved patterns (right). You can select a pattern with the pull-down menu in the menu bar. Many patterns come with the software, but it's possible to create your own. The pink arrow indicates an image of cherry blossoms from a photograph that I defined as a pattern.

Open a new file and choose a pattern. I will use the cherry blossom pattern for this example. With "Aligned" checked, draw on the image. If you draw over the entire image, it will give the same effect as if you had used Fill to fill the image with the pattern. If the pattern is smaller than your image, it will tile repeatedly to fill the available space. No matter how many times you click as you draw, once you have drawn on a part of the image, the picture does not change. My example is shown in the picture (left).

Now uncheck "Aligned" and try drawing again. This time, if you release the mouse button and click again, the pattern starts up from a different point. If you draw over a previously drawn area this way, the image changes. My example is on the right.

Finally, check the "Impressionist" option in the menu bar. Try drawing and see what happens. This time your brush doesn't leave a plain pattern, it leaves a trail of multicolored dots in the shape of the brush. Changing the brush leaves a differently shaped trail. In my example, I used a circular brush and a custom bunny-shaped brush (left).

The question is, how do you save patterns to the pattern menu? First you have to create the pattern. You can use a part of a photograph, like the cherry blossom pattern, though that doesn't make a very good pattern tile because it has sharply defined edges where the pattern repeats. You may have to extract the object in the photo from its background first, or at least blend the edges so that they run smoothly together. You can also use the Pattern Maker filter to turn a section of an image into a pattern tile, as demonstrated in Lesson 10. A third option is to use filters to make a pattern you like, such as the woven-look pattern created in Lesson 11 (right).

Once you have the pattern, use the Rectangular Marquee to select the area you want to be a single tile. Then go to Edit → Define Pattern and type in a name for your new pattern. That's it! The pattern you saved now appears on the pattern menu (left). You can use it with the Pattern Stamp tool, as well as with the Paint Bucket/Fill function, Layer Style, and any other time a pattern is an option. You can delete items from the pattern menu at any time if you no longer need them.

Now that you know how to define a pattern, the next step is to define your own custom brushes, such as the bunny used above. To the right is the original drawing from which that brush was made. Decide what kind of image you want for your brush and draw it in simple black and white. (If you try to use color, it will still only be saved as a grayscale image.) You don't have to be an artist to draw a new brush. This bunny was done using only the Elliptical Marquee tool; it has three black ellipses for the face and ears and two white circles for the eyes.

Drawing a crisp black and white image like this bunny gives you a crisp brush. Drawing an image with grayscale shading gives you a grayscale brush. One problem that you run into with a grayscale or grainy brush is that it can sometimes appear very faint and require multiple clicks to be visible. The numbers under the butterflies (left) indicate how many clicks it took to get that intensity. You could also use the airbrush function and hold the mouse button down until the brush has laid down enough paint. Grayscale brushes such as this are useless with the Pencil tool, because the pencil only draws sharp outlines with no anti-aliasing.

Once you have your desired brush image, select it with the Marquee and click Edit → Define Brush, then give your new brush a name, exactly as you did when defining a new pattern. The new brush will appear in the Brush menu. You can use it with all tools that make use of the Brush menu, such as the Eraser, Blur, the History Brush, the Healing Brush, and so on.

There are extra brush tricks that you can add to your new brush using the Brush palette (right). The first item on the menu lets you select the brush from the menu. Here I've chosen the bunny.

"Angle" sets what angle the brush is tilted. "Roundness" allows you to squash the brush shape. "Spacing" sets how far apart each iteration of the brush shape is painted. The pictures below illustrate these properties.

Angle: 45°	Angle: 90°
Roundness: 25%	Roundness: 50%
Spacing: 1%	Spacing: 100%

The Shape Dynamics sub-menu allows you to control the size of the brush. "Size Jitter" makes the size of the brush change randomly as you draw. The pull-down menu beneath this item changes how this size change is applied. "None" means that you have no control, the computer applies the jitter randomly. "Fade" makes the size begin relatively large and then grow gradually smaller according to how many "steps" you input. These properties are illustrated below. The remaining options are only valid if you have a stylus and pad connected to your computer.

Size Jitter: 50%

Size Jitter: 100%

Control: Fade 10

"Minimum Diameter" controls how small the smallest iteration will be (below). These pictures were both done with 100% jitter.

Minimum Diameter: 1%

Minimum Diameter: 50%

"Angle Jitter" makes each iteration of the shape appear at a random angle (below). The extent of the angle change is determined by the percentage.

Angle Jitter: 20%

Angle Jitter: 50%

"Roundness Jitter" randomly squashes the brush shape. The next item, "Minimum Roundness," sets the extent to which the shape can be squashed--the higher the number, the less it is squashed. These two items are illustrated below.

Roundness Jitter: 50%	Roundness Jitter: 100%
Minimum Roundness: 1%	Minimum Roundness: 50%

The Scattering sub-menu makes the iterations of the brush shape vary in other ways. "Scatter" makes them randomly appear above or beneath the line that you draw. If you check "Both Axes," they will also scatter in front of and behind the point you click. "Count" varies how many iterations are painted, and "Count Jitter" randomizes the count. If you don't scatter the iterations, the "Count" function will paint them directly on top of each other, making them appear more bold the higher the count. These properties are demonstrated below.

Scatter: 100%	Count: 1	Count Jitter: 50%
Scatter: 400%	Count: 2	Count Jitter: 100%

The Texture sub-menu allows you to apply a texture to your brush. The textures are drawn from the pattern menu, so you can use Define Pattern to create your own. This example uses the Gauze pattern on Subtract mode (left).

The Dual Brush sub-menu allows you to combine two different brushes. In this example, I combined the bunny brush with a brush called "Stencil Sponge - Twirl" from the default menu (right). You can alter the size and count of each brush in relation to each other as well as adjust how they blend.

The items on the Color Dynamics menu let you randomize the properties of the color, as illustrated in the pictures below. For these pictures I selected pink as the foreground and white as the background.

Foreground/Background: 50%	Foreground/Background: 100%
Hue Jitter: 50%	Hue Jitter: 100%
Saturation Jitter: 50%	Saturation Jitter: 100%
Brightness Jitter: 50%	Brightness Jitter: 100%
Purity: -50%	Purity: +50%

The Other Dynamics sub-menu randomizes the opacity and flow of the paint. Examples are shown below.

Opacity Jitter: 50%	Opacity Jitter: 100%
Flow Jitter: 50%	Flow Jitter: 100%

The remaining items don't randomize, but instead add certain qualities uniformly to your brush. In particular, note the dithering of "Noise" (left) and the outline of "Wet Edges" (right).
In addition to the pattern menu and the Brush menu, there is one other place where you can save selections while you work, and that is the Channels palette. After setting my bunny brush for various levels of jittering, I painted the picture on the left. The Channels palette for this image is shown on the right.

When you are working in RGB mode, your image is composed of the colors red, green, and blue mixed together at varying degrees. The Channels palette shows you what each color looks like when separated from the other two colors.

Like a mask, each channel is represented in grayscale. The lighter the gray, the more that color is applied to the image, and the darker the gray, the less that color is applied. White is made up of all three colors at full strength, so any white areas of your image will also appear white (full strength) on all three channels. Black, on the other hand, is made up of the absence of all three colors, so any black areas of your image will appear black on all three color channels.

Any channels over and above these three are called "alpha" channels, because they are "plus alpha" compared to the default. There can be a total of 56 channels, which means that you can add 53 channels on top of the default three. (If you are working in CYMK mode, you have four default channels, instead of three.)

When you make a selection in your image, you can choose to save that selection area as an alpha channel by going to Select → Save Selection or by right-clicking with your selection tool and choosing Save Selection from the pop-up menu. A third method is to go to the Channels palette and click the "Save selection as channel" icon at the bottom.

In this example, I used the Magic Wand to select a single bunny and then saved the selection area as an alpha channel (left). The advantage of doing this is that this alpha channel can now be used as the equivalent of a stencil. I can call up this selection area again at any time with Load Selection (as discussed in Lesson 11). This way your "stencils" don't have to be extra layers in your image, you can save them out of sight in the Channels palette and only call upon them when needed. Most sophisticated techniques that require complicated selection areas use alpha channels to store information.

Separate selection areas can be stored as separate channels, or you can add and subtract selection areas from each other.

Homework

1. Create and save a pattern to the pattern menu.
2. Create and save a brush to the Brush menu, then use the Brush palette to alter the characteristics of your brush and draw with it.
3. Select something in your drawing (or in a different image) and save the selection area as an alpha channel.