Vector vs. Raster  E-mail
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Written by Craig Watkins   

One of the most important things to understand about Illustrator is the difference between vector based images and raster based images.

Required reading for Beginners!!!!

This is all text, but forms a crucial building block to understanding Illustrator. Please take the time to give this a read!
Illustrator creates VECTOR BASED IMAGES. Vector images are created by using mathematical equations to define the shapes and points of the image. If the image is increased in size, the equation is recalculated accordingly resulting in the image increasing in size with no loss of data or detail. As a result, resolution (the quality of the image at varying sizes) is not an issue in Illustrator.

(By the way, all of this math goes on “behind the scenes” so you don’t have to understand anything more than why it works in theory and when to use it!)

Saved file sizes are smaller when created by Illustrator because everything is defined mathematically rather than by pixels.

Vector programs do not handle photographs as well as a general rule.

RASTER BASED IMAGES (Adobe Photoshop is raster based.) are created using a grid of pixels to define the image. Each pixel is assigned a color value and all of the pixels together create the image. When you attempt to increase the size of an image created in a raster based program, the pixels defining the image can be increased in either number or size. Increasing the number of pixels or making the pixels bigger in an image results in the original data being spread over a larger area. Spreading the pixels over a larger area causes the image to begin to lose detail and clarity.

Raster files handle the subtleties of photographs very well as a general rule. Raster files can be very large if there is a large amount of detail and pixels in an image.


Both vector and raster based programs are extremely important to the graphic designer. More important is knowing the difference between raster based programs and vector based programs and which type of program to use in different situations.

For example: If I’m creating a logo for a banner that is going to be reproduced at a size of 6 feet wide by 4 feet tall, I’m going to use Illustrator to do this. Here’s why. I can create the logo at any size in Illustrator and the logo can be scaled to fit the banner and I won’t lose a single bit of quality in my logo. As I increase the size, the mathematical equations defining the logo are increased as well.

On the other hand, to insure the quality of my logo created from a raster based program like Photoshop, the only way I can be 100% sure how it will look at it’s finished size is to create the logo at the finished size of 6 feet by 4 feet, or create it at a proportionately smaller size and a proportionately larger resolution. If the logo happens to be fairly complex created at this size, obviously the file size will be much larger. Take it from me, this task takes a lot more work to be performed in Photoshop, and there are a lot more things that can go wrong.

A vector based file is simply a much more versatile file to work with. You can do almost anything with it, mostly because resolution is not an issue. The tiniest vector based file could, in theory, cover the face of the Empire State Building and look just like it did on your screen!

Here’s another example: I’m working on a logo for a client and I may want to edit the logo after they see my first attempt. They’ve decided they want the type color and the shape I’ve used behind the type to change. This is an easy fix in Illustrator because practically everything is fully editable in Illustrator at all times. Days, weeks, months, years later! In Photoshop, the type color is easy enough to change, but I’ll most likely have to completely recreate the shape behind the text. Then they change their mind again... and again... and again... and I have to recreate the shape every time from scratch. In Illustrator, I can easily edit the existing shape without starting over every time.

Illustrator does not offer as many options as far as cool looking effects as Photoshop does until you have a relatively high skill level with the program. (Anything can be done if you’re willing to take the time to do it!). However, the beauty is that you can import your vector images created in Illustrator into Photoshop and apply effects to them. You create your basic logos or shapes in Illustrator and take them into Photoshop to add a greater variety of effects like in this tip: Exporting Illustrator Files to Photoshop.

Once the file is saved in Photoshop, however, you will lose a lot of your editing options, but you will still have your basic vector image saved in Illustrator if you need to regroup and try again. The opposite of this does not work. You cannot take a raster (Photoshop) file and import it into Illustrator and have it become a vector file. The file will still be constrained by the parameters set for it as a raster image. The point is.... if it’s not a photograph, start in Illustrator and save yourself the headaches!!!!!!

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