Using Adobe Illustrator CS2’s Live Trace

Step 1: Create and Scan Your Image

I’ve started with a rough sketch with a Col-Erase carmine red pencil, then inked it using Pigma Micron pens. I work this way because it allows me to sketch roughly, then ink over what worked in the scribbles and (as you’ll see) easily remove the red in Photoshop.

This image is nothing special, just a quick and reasonably simple image for demonstration purposes. Scan in your image at a fairly good quality. The more detail you have, the more Live Trace will have to work with. I scanned this at 300 dpi to a PNG file. You can download this file and work along by right-clicking (or CTRL-clicking with a Macintosh one-button mouse) this link and save the image to your computer.

Step 2. Prepare Your Image

Open the file in Photoshop. Open Hue/Saturation (Image>Adjustments>Hue/Saturation or ?-U, CTRL-U on PC). Set the channel to Reds and set the lightness to +100. Some of the lines fall within the Magenta channel: Change the channel to Magentas and set the lightness to +100 as well. Click OK.

There may be some light grey lines left over, but the black and white tracing method we’ll use in Illustrator is going to ignore them. So save the file and proceed to the next step.

Step 3. Place Your Image in Illustrator

Open Illustrator and create a new document. Use File>Place and place the file you just saved into the document. Go ahead and save your Illustrator file as livetrace.ai.

Step 4. Perform the Live Trace

Zoom in on your newly placed image. You won’t be able to zoom in on the image while working with the Live Trace tool, so you’ll want a good view before you begin. Click on your placed image with the selection tool; a bounding box will appear around it. Now choose Object>Live Trace>Tracing Options. You could do an automatic trace using Object>Live Trace>Make, but then you’d need to go back and the adjust settings for the best results.

We want a nice clean black and white drawing, built of strokes, since they are easier to edit. Even with a trace, you’ll likely want to do some node editing and strokes are easier to work with. Keep Mode at Black and White, and keep Threshold at 128 (this means anything darker than 50% grey goes to black, anything lighter goes to white, 128 is half of 256, which is the maximum number of colors). Set Trace Settings so that Strokes is checked and Fills is not.

Now check Preview so that you can see what the final result will look like. This will alter every time you change one of the parameters in the Tracing Options menu.

The next important option is Max Stroke Weight. When tracing strokes, this option determines how thick the thickest stroke in the trace can be. If a scanned line is thicker than this number, it is outlined instead. See the example below, where the eyes, the chin and other parts have lines too thick for the setting (currently set to 10 on my system).

I set the Max Stroke Weight to 20, and the problem is fixed. You may need to play with this a bit. But now you may notice another problem.

A couple of lines are missing: tooth lines and the lines where the chin enters the face. You can click Preview on and off to compare the trace to the original, spotting this sort of problem. These lines are missing because my Min Stroke Lenght is set to 20px. Any line that is shorter than 20px will not be drawn, and obviously the missing lines are too short. I set it to 10, and the problem is fixed. Your mileage may vary.

If you want to know more about the other options, go to the Illustrator Help section for Live Trace and read about them there. Or simply adjust them and see what happens to the monkey. Once things look good to you, click the Trace button. Voila!

The image above is my final trace. It still has that blue box around it, since this is still a Live Trace object. As long as it’s “Live”, you can go back to the options and make adjustments. You may be happy with this, but I see some things I’d like to fix: some of the line weights could be adjusted and some of the corners are a bit sharp. So, I’m going to commit to this so that I can edit the strokes.

Step 5: Manual Editing

Now I want to do some manual editing. To make it editable, we’ll have to finish our Live Trace session. Select your drawing, then choose Object>Live Trace>Expand. This changes the Live Trace object into a standard, editable group of strokes. You’ll need to ungroup these strokes to edit them individually (Object>Ungroup). Then, you can do whatever Illustrator editing you wish.

I’ve smoothed some lines, changed some line weights and rounded a few curves, nothing too time-consuming. This project took me around 5 minutes from scan to final: Once you’ve got the workflow down, the Live Trace saves a lot of time. And I now have a smooth Illustrator vector version of my drawing with less work than it would have taken in older versions of the program.

And now it’s ready for color with the new Live Paint feature. But that’s another tutorial. I hope you found this useful: drop me a line if you did, if you have questions, or if you have constructive comments.

Learning More About Adobe Illustrator

Though it seems daunting at first, Adobe Illustrator is a power tool for creating exciting works of art. Austin-based Square Bear Studio provides tutoring in mastering this complex program, either in person in the Austin area or remotely through Skype. Contact us for more details.