Learning About Labels -
Vector vs. Raster Files

Vector vs. Raster Files : What's the Difference? ?

For years I never understood the difference between raster and vector image files. For some reason, I found the concept difficult to understand and I imagine there are others in the same boat. So here is a simple explanation of these two kinds of files.

Let’s start with an example. Look at the two M characters in the right column. They are both 8 point Verdana font, or at least they started out that way. I created the M on the left in Photoshop and the M on the right in Illustrator. I then increased the size of both letters by 1000%. You can see that the M on the right has maintained its smooth lines and still looks good, whereas the M on the left has lost its sharp lines and looks fuzzy.

The M on the left is a raster image (also called a bitmap image). A raster image represents an image as bits of information that translate into pixels on the screen. Because these pixels are very small, a raster image normally appears as a smooth image. You only notice the pixels when you magnify the image. If you magnify the image enough, as I did with the M here, you lose the sharp lines and details.

Creating a vector image takes a completely different approach. Vector images are based on a mathematical formula that defines curves and lines, enabling you to scale an image much larger or smaller without losing anything in image quality. As you can see ,the M that I created in Illustrator lost nothing when it was magnified by 1000%, so for this reason vector-based images are always best when working with text.

Illustrator creates images as vector files, unlike Photoshop. Feel free to create any graphical elements in Photoshop, but import the design into Illustrator when you are ready to add text. There is a noticeable difference in print quality between text created in Illustrator versus Photoshop. A rule of thumb is to not create text smaller than 14 point in Photoshop; Illustrator will give you a distinctly better result.

(Peter Renton)