One gazillion years ago (I call it 1989) I used a rather nifty application called Adobe Streamline. It had the ability to convert pixel-based bitmapped images into a vector graphic image.
But why would you need that? It is due to the adage of while you can shrink a low-res image, you can’t enlarge it. That’s because a bitmapped image is made up of pixels. Blowing them up only creates larger pixel areas creating that all-too-familiar crappy Youtube video look. With vector graphics an image is drawn through points and calculated lines. I like to tell my classes that it is like the computer is drawing with math by playing connect-the-dots. The downside to vector graphics is that if an image is too complex, this creates more and more areas which become clunky for the computer to redraw. Simplistically, if it’s complicated image and you want photographic detail it is best to go with bitmap. For images which are simpler in terms of line and color such as type, web graphics, or logos then vector-based artwork is usually the way to go. With programs such as Illustrator, you could always export to bitmap. With Adobe Streamline, you could take an image and convert it to a vector-graphic. It was clunky, and the interface sometimes left much to be desired, but it did the job. Unfortunately, it dropped off my personal radar around the mid-90s, although it’s last incarnation was 4.0 released back in 1997. Around Adobe CS2’s release, a function in Illustrator called Livetrace turned up. It turned out to be the same functionality of Streamline, but in a much more elegant execution.
Let’s say you want to make a logo that you just placed into Illustrator out of this stock photo for your studio "Baker Street Design." You want the image simplified for use in black & white, grayscale, and color. Right now in its bitmapped form it would be tedious to go in and redraw and recolor it only to have something that would be as equally tedious to re-size without it aliasing all over the place. But, it’s got the basic elements and look you want.
Here I’ve brought the image in Illustrator CS4 (although the commands and look are basically the same in CS 2 & 3.) It is a good strong contrast image to start with. I select the image and hit "Livetrace" at the top:
Below left is the original image, and below right is one with the default settings which is a "Simple Trace."
It’s not quite the look I’m going for, so I go to the Livetrace options menu in the top left area of the menu bar at the top. I select "Photo Low Fidelity" which knocks it into what looks like a posterized image in Photoshop:
Right now there are still too many colors. So I adjust the Threshold slider to reduce the amount of colors to taste.
Here, after some experimentation, I knocked it down to 11 colors.
However, I don’t like the color of the lamp glass, and would like to play with it. I select the image and then hit "LivePaint" at the top.
As you can see, there are a lot of areas of color shapes, including the background. All the individual color areas now have been converted into a vector shape which can be painted with the LivePaint Paint bucket tool in the toolbar menu. I select a bright yellow for the color version of our logo and paint the glass areas. Notice the red line which indicates the vector shape you are painting.
tip: It’s worth your while to examine your image zoomed in to make sure you do not miss a tiny vectorized area.
So, it is looking pretty good, but ideally we would like just the lamp and not have this big off-white area around it getting in the way of our future logo plans.
To do this, select the white arrow tool from the toolbar. This allows you to select points and areas instead of the entire piece. I draw around the spots I want to eliminate and hit delete, careful not to hit any areas that I want to keep. To check your work, hit the black arrow selection tool and select your piece to find areas where you may have missed. You may have to go back and forth several times.
Voila! After cleanup you have a finished vectorized graphic which you can further manipulate in Illustrator and/or recolor as needed with LivePaint.