Chapter 6: Vector Art in an Eggshell

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This chapter shows you how to use the multitude of tools and Xtras in FreeHand, and what you can do with them in the fine art of vector art.

What's Vector Art?

"Computer artwork" consists of two main groups of images: vectors and bitmaps. Macromedia FreeHand and Adobe Illustrator are examples of vector drawing programs. Macromedia Fireworks and Adobe Photoshop are both bitmap or raster imaging programs.

A vector is the product of a mathematical formula that calculates the curve of a path between two anchor points. This formula uses the x and y coordinates and the angle and length of the control handles of each point to determine the amount or degree of the curve. A vector path is resolution-independent, meaning that no matter how much a path is enlarged or reduced, the visual sharpness of the curve remains constant; the file size also remains the same. A one-inch square drawing has the same file size (20k) when printed at that size, or enlarged to a three-foot square.

A raster images consists of a grid of cells called pixels. Each pixel has a specific color and location, and if you are editing a raster image, you are actually editing individual pixels by changing their color. Raster images are resolution-dependent, meaning that they have a finite number of pixels that create the image. If the image is enlarged, the image gets larger by definition, but so do the pixels, and the image becomes blocky or "gets the jaggies." (See Figure 6-1.) The small graphic on the left is the original drawing. It was exported to Photoshop and printed at the same size to the right of the vector drawing. Then the drawings were enlarged to show what happens to pixels when an image is expanded. The black line is easily five times wider than the white line, but when you reduce it to a finite number of pixels per inch, the bitmap uses barely twice as many pixels to portray the black line as it does the white line.

Figure 6-1: Notice the differences between vector and bitmapped artwork at various enlargements.

In contrast to a vector image, a 300 dpi (dots per inch resolution), one-inch square RGB drawing is 264k, and the same drawing at three feet would be a whopping 333.7MB! If you simply enlarge the one-inch square to three feet, each pixel would be approximately an eighth of an inch square, creating a pretty blocky image.

This is not to say that vectors are good and bitmaps are bad. They are used side by side in many projects. Vectors are often used in preliminary work for a project that will be finalized in a bitmap program, and the opposite is also true. To complicate matters a little, Adobe has added raster effects to Illustrator so it's possible to make a vector-based drawing, add subtle shading and color mixing, and rasterize the final drawing. That drawing is a resolution-dependent bitmap, however, not a vector drawing. If you wish, you may convert your vector graphics to bitmaps using the Rasterize command. When you do the image becomes an embedded TIFF file that will reside in the FreeHand document. You will lose the resolution-independency.

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