All About Raster and Vector Files

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 out there 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's above. These 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 these M's by 1000%. You can see that the M on the right maintained its smooth lines and still looks good, whereas the M on the left has lost its sharp lines and details and looks fuzzy.

The M on the left is a raster image (also called 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 try and magnify the image. If you magnify the image enough though, as I did with the M here, you lose the sharp lines and details.

A vector image takes a completely different approach. It uses a mathematical formula to define curves and lines which enables you to scale an image much larger or smaller without losing anything in image quality. As you can see the M 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.

A couple of weeks ago I wrote about creating product labels in Photoshop. Photoshop is an excellent tool for creating art but there is one caveat that we tell our customers. Once you are ready to add text to your label import the design into Illustrator and add the text there. This will ensure your text always looks crisp and sharp even for very small type.

With our high resolution digital label printing press you can really tell the difference between text created in Photoshop and text created in Illustrator. A rule of thumb is any text smaller than 14 point do not create in Photoshop; Illustrator will give you a much better result. If you don''t have Illustrator or are worried about the quality of your text, our in-house graphic designer will be happy to help you.