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Brush menu

(below).


Under the number one you will see the brush tip pulldown menu. Clicking on this menu shows you a variety of different brush shapes and sizes. (You can change the way the brushes are listed, whether with text or thumbnails, by clicking on the triangle button in the upper right corner of the box.) Clicking on one of the options in this menu changes the shape of the brush. It is possible to design your own brush and save it onto this menu, but that will be addressed later.

You can change the size of the brush, and consequently the width of the line it draws, by moving the "Master Diameter" slide or by typing in a number of pixels.

The number two indicates the menu governing the drawing mode. This is a more advanced property of the brush. For now, leave it on the default.

The third item, "Opacity," governs how see-through the "paint" with which you are drawing is. Reducing the opacity makes the paint appear fainter. When the opacity is low, painting over the same area multiple times adds "thickness" and makes the color darker.

The fourth item, "Flow," determines how much paint flows from your brush. The effect looks similar to reducing the opacity.

The number five marks the "Airbrush" button. Clicking this button toggles the airbrush property on and off. When the airbrush property is activated, the flow of paint increases the longer you hold down the mouse button over a certain spot.

As with drawing pictures in the real world, where would we be without an eraser? Click on the Eraser tool icon, then click and drag your cursor across your image. Since this is the background layer, the effect of the Eraser tool is to turn the area that it touches into the color specified as the background color. (On other layers, the Eraser makes what it touches transparent. This will be explained in more detail in the lesson involving layers.)

The Eraser menu looks almost the same as the Brush menu. The difference is that it only has three modes: Brush, Pencil, and Block. This allows the edge of the Eraser tool to be feathered like the Brush or sharp like the Pencil. The third item, Block, makes the eraser into a square of a fixed size.

The Brush, Pencil, and Eraser tools work on digital photographs as well as on blank canvas images. The Background Eraser tool, in particular, can be useful when altering photographs. Open a saved photograph (or one of the flower pictures from these lesson pages) and select the Background Eraser tool from the toolbar.

If you use the plain Eraser tool, it will turn whatever it touches into the background color. The Background Eraser tool turns the background transparent. With the Eraser tool, if you wish to erase the background from around an object in a picture, you have to be very careful when going around the outline of the object you want to keep so that you don't erase part of the object itself. The Background Eraser tool helps alleviate this problem by erasing only specified colors.

Unlike the Eraser tool cursor, which is a plain circle, the Background Eraser tool cursor has crosshairs in the center. These crosshairs are used to sample the colors that the Background Eraser will erase. Take a look at the Background Eraser menu.


Item number one, the "Brush," allows you to determine the size and shape of the cursor.

The second item, "Limits," tells the tool whether it should erase contiguous areas or not. Unlike the Magic Wand tool, it will not erase anything it does not touch when it is set for non-contiguous. It will, however, erase non-contiguous areas that are contained within its cursor space.

The third item, "Tolerance," acts like the Magic Wand tolerance in determining how close in color a pixel must be fore the eraser to delete it.

If you use the Eyedropper tool to set the foreground color to the color of the object you want to keep, you can then check item number four, "Protect Foreground Color." This helps prevent the tool from mistakenly erasing the object you're trying to keep.

The "Sampling" item, number five, tells the tool how to determine what color to erase. "Continuous" means that it keeps sampling whatever color is under the crosshairs, so that the color changes as the tool moves across the image. "Once" indicates that the tool will sample the color under the crosshairs the first time you click and will not change the color as long as you hold down the mouse button. "Background Swatch" tells the tool not to sample from the image but instead to erase based on your chosen background color.

The pictures below illustrate the use of the Background Eraser tool. The gray checkered pattern in the middle picture is Photoshop's way of showing transparency. Note that the final picture still has some "garbage" left and isn't completely transparent. This means the tolerance wasn't set quite high enough. However, for a fast once-over, it makes it much easier to extract the flower using a rough pass with the Lasso, or you could continue to erase the garbage with the Eraser.

 


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In addition to the Background Eraser tool is the Magic Eraser tool. This tool acts quite similar to the Magic Wand tool, except that it erases rather than selecting.