The Difference Between Vector Files and Bitmap Files

Have your ever heard the following; "can you send me that logo in vector format?". Have you wondered what the heck a vector file is? What about your photos? You've heard those files are bitmap files. So what does all that mean and how can knowing the difference between vector and bitmap files help you? Well, the short answer is that vector files are made up using mathematical information and bitmap files are made up of pixels, little squares of color information to build an image. Ok, so here is how that translates into the real world.

Bitmap Images
A bitmap image is as the name implies. A series of colored bits to map an image. Think photographs here. The image is made up of a series of individual tiny squares, or pixels. Each pixel has it's own color information and with thousands of pixels lined up side by side you get a photograph. Because each pixel is so small, your eye will see a nice transition from one color to the next and you won't notice them individually. You can have drawings (or logos), line art, or photographs as a bitmap file. Your images pixel resolution will determine how many pixels make up your image. The higher the resolution the better the quality. For printing, an image resolution of at least 250dpi is generally a good rule to follow. For web files (like sharing those photos, a lower resolution of 72 dpi is required. Be careful when saving bitmap files, they are generally big. Bigger then vector files because each pixel contains information to build your image. Bitmap files are generally saved as .jpgs or .tifs and edited in applications such as Photoshop. Tip: You can save vector files into a bitmap file format (like .jpg or .tif) but nice vice versa.

Vector Files
Vector files are built using mathematical information instead of using pixels. The files are built using lines and points that connect using strokes and fills to add color. These files are usually logos or drawings or maps. Sorry, no photos here. The main advantage to having a vector file is it's scalability. No matter what size you make it, it will always print great. Want your logo on a business card? Done. Want your logo on forty-foot banner? Done. You just can't blow a photo up that big or shrink it that small and make it look good. Because a photo has a set number of pixels per inch, you just can't scale it to the extremes and maintain a nice resolution. Since a vector file is all math, you can maintain nice clean lines no matter what the size your vector file is. Vector files are usually saved as .eps files from programs such as Illustrator, Freehand, or Corel Draw. Tip: You can open a vector .eps file and edit it in a bitmap image editing program such as photoshop but you will lose the scalability of your file since you just switched it from vector to bitmap.

Hope that helps!