Lesson 3

Color, drawing, and erasing

Look down near the bottom of the toolbar and you should see an area with two overlapping squares of color. The square on top is called the foreground color. This is the color that you "paint" with when you draw using the brush or pencil tool, and it also has other purposes. The color partially hidden beneath the foreground color is the background color.

The default setting is black in the foreground and white in the background. You can return the colors to the default at any time by clicking on the tiny black and white icon to the lower left of the color squares. If you wish to reverse the order of the two colors, switching the foreground for the background, you can do this by clicking on the double-headed arrow to the upper right of the two squares.

There are several ways to change the foreground and background colors. The first way is to click directly on the squares. When you do so, the "Color Picker" dialogue box appears, as in the picture (right).

You can use the Color Picker dialogue box to set the color in several ways. If you hold your cursor over the large square filled with a gradient of color, it will turn into a circle. Click the gradient, and whatever color is in the center of the circle will be displayed in the upper half of the color icon to the right of the spectrum. The lower half of this color icon will remain set at the previous color so that you can compare the original with the new color you are selecting.

By moving the triangular arrows on the spectrum, you can change the color displayed in the gradient box. You can also click directly on the spectrum itself.

If you know the numerical value of the color you want, whether it is an RGB value, a CMYK value, a hexadecimal value (used when coding web pages), or some other value, you can type the number directly into the appropriate fields. You will probably use RGB values most frequently. An RGB value is made of three numbers, each ranging from 0 to 255. The first specifies the amount of red, the second green, and the third blue. If all three are set to 0, the result is black. If all three are set to 255, the result is white. If all three are the exact same number, the result is a shade of gray.

To the right of the color icon is a small cube icon with a tiny colored square beneath it. This is to indicate a "web safe" color. There is a limited selection of colors that are called "web safe"; if you are composing a web page, it is considered best to stick to this range of colors so that they will display properly for all users. The color in the tiny box below the cube will display the closest "web safe" color to the color you have chosen. Clicking on the tiny box will select that color.

Another color-related problem that crops up is the difference between the RGB spectrum and the CMYK spectrum. Working in RGB mode is fine if you intend your finished product to be displayed electronically. However, if you intend to print it out using a standard four-color printer, it will automatically be converted into CMYK mode first, so that the printer knows how much of each color ink to use. The difficulty here is that, with these four colors alone, the printer cannot reproduce the full range of colors that are available to you in RGB mode. In particular, it cannot reproduce the brightest colors, so the printed image will look more "dull" than it did on your monitor.

While you are working in RGB mode, if the color you select is not a color that can be printed accurately in CMYK mode, a warning exclamation point will appear above the "web safe" cube icon. Thus, if you intend to print the image, you should watch out for the warning icon and be aware that the color you see will not necessarily be the color you get.

If you have an image open that you are working on, you can also select a color from that image. Move your cursor over the image, and it will change appearance to look like an eyedropper. Click the tip of the eyedropper on the color you want from your image, and that color will be selected in the Color Picker.

When you are satisfied with the new color you have chosen, either press Enter or click the "OK" button.

If you want to select a color from your image without going through the process of opening the Color Picker dialogue box, you can instead click on the Eyedropper tool. Your cursor will turn into an eyedropper and you can click on the desired color. The color you choose will then become the foreground color. (To change the background color, click the double-headed arrow, use the Eyedropper tool, then click the double-headed arrow a second time.)

There are helpful keyboard shortcuts for these actions that can save you a lot of time if you are doing serious painting. While you are painting, if you hold down the Alt key, your cursor will turn into the Eyedropper until you release the key. Also, the D key resets your foreground and background to the default, while the X key swaps the foreground with the background.

Another method to set the color is to use a "palette." A palette is a menu that you can either leave open on the workspace or hide so that it is out of your way. There are many different palettes, and you can control their appearance with the Window menu. The Color palette is pictured on the right. When you hold your cursor over the spectrum on the Color palette, it automatically turns into an eyedropper. You can also change either the foreground or background colors by clicking on the appropriate square on the Color palette and choosing RBG values with the slider or by typing the numerical values into the fields.

In addition to the Color palette, you can also use the Swatches palette, pictured on the left. The "swatches" are like the paint samples that you use when choosing a color to paint your house. They are set values that you can choose by clicking on the square of the color you desire. The advantage of using swatches is that, unlike picking from a gradient, it is quite easy to return to the exact color that you used previously because the swatches always remain the same. If there is a color you want that is not on the Swatches palette, you can either load a different sample of swatches, or you can choose the color using one of the other methods and then add that color as a new swatch. That way you can come back to it again and again.

Now that you know how to select colors, choose a color that you like for the foreground and create a new image. When you create the image, make sure you check that the background color is white. It's time to start drawing.

There are two main tools used for drawing: the Brush tool and the Pencil tool. The difference is that the Pencil tool has a distinct, sharp edge, while the Brush tool has a softer edge. The Pencil tool is useful when you are doing very fine work, particularly on the pixel level, where the soft edge of the Brush tool would introduce distortion.

For now, choose the Brush tool, because it is the default. Click and drag the brush across your image. It should leave behind it a trail of the foreground color. Switching to the Pencil tool will give you a similar result but with harder edges. The image on the left illustrates smiley faces drawn with the Brush tool (left) compared with the Pencil tool (right).

After you have familiarized yourself with drawing, look at the 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.




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.


Use the Brush, Pencil, and Eraser tools with various colors to experiment with drawing pictures. Try both creating completely new images as well as drawing or erasing on digital photographs.