Tutorial: Bundle of Snakes – Tracing a Sketch in Illustrator, from Pencil to Vectors

We’re going to be creating a vector image (line art) from a hand-drawn sketch, using Illustrator’s Live Trace tool. This involves drawing, scanning, cleaning the image in Photoshop, tracing and adding color in Illustrator.


I started doodling at the end of a small notebook and came up with a bundle of snakes that filled the page. I drew them using a 0.5mm pencil, then erased most of the pencil and redrew the lines with a red pen.
Then technique is not that important as long as you come up with a fairly clear result. Clean, strong lines are easy to trace.

Bundle of Snakes - Doodling at the back of a Notebook

Cleaning up in Photoshop

Bundle of Snakes Tutorials: Photoshop Levels ToolScan your sketch (make sure you use a decent dpi) and open the image in Photoshop. We’ll be working with a grayscale image (Image Menu -> Mode -> Grayscale). You’ll want to adjust the brightness, contrasts and levels (Image Menu -> Adjustments). You’ll quickly get used to the way the Levels and Curves tools work. Your goal is to get a clean black and white image. You don’t want specks and shades in the white background, but you also don’t want the black lines to become jagged. If you need to, you should use a brush to paint black or white to get rid of unwanted artifacts. Try the eraser. Also crop if necessary.

The best tool to get your image even cleaner is the Color Range Tool (Select Menu -> Color Range). It lets you define a color you want and will select it for you. Just by using the default settings, I used the eyedropper to select a black area. The preview pane is of some help so you can understand what you’re selecting (white in the preview means it’s been selected). Once you have the selection, create a new layer and fill it black (Edit Menu -> Fill). Hide all other layers and you should have the result on the right. Save the file.

Bundle of Snakes Tutorial: Cleaned Image in Photoshop

Live Tracing in Illustrator

Open the PSD image in Illustrator. Select the menu near the Live Trace button and click Tracing Options. This is the Live Trace tool. You’ll need to play around with the settings to find a set that works for your particular image.

The Threshold is the “limit” between black and white. Setting it higher will add more black. Adjusting some of the other settings will yield different results. Check “Preview” to see what you’re doing and “Ignore White”. My settings are below. You might want to save the preset. If you need to go back to Photoshop to clean certain areas, do it now. Then come back to Illustrator and re-trace using the preset you saved.

Bundle of Snakes Tutorial: Live Trace Illustrator Settings

Path Editing

Depending on your sketch and the settings you used for tracing, the paths that were created are more or less smooth and close to what you want. This step is entirely manual and means you have to manipulate the anchor points of the vector paths to get them to look exactly the way you want. I didn’t spend much doing this, just corrected some things I didn’t like.

Your friends are the Pen Tool and the Add/Delete/Convert Anchor Point, plus the Knife or Scissors if that helps. Use Outlines (Cmd + Y) to better see what you’re doing.

Bundle of Snakes Tutorial: Path Editing in Illustrator - Anchors

Live Painting in Illustrator

The very cool Live Paint Tool will let you fill areas of your image with color. If your colors are stuck in Greyscale, click the Palette menu and choose RGB or CMYK. Now fill with color as needed. I experimented with a few colors before settling on the orange/blue scheme.

Bundle of Snakes Tutorial: ive Painting in Illustrator 1

Bundle of Snakes Tutorial: Live Painting in Illustrator 2

Finishing Touches

I cleaned my Illustrator layers and groups and got them organized the way I like them. I then selected one of the orange fill and did a Select -> Same -> Fill color. Then I merged all of them together using Pathfinder’s Unite Button (Alt + Click, then choose Expand). I did the same for the balck outlines. I was left with 3 compound shapes: the orange fills, the black outlines and the blue backgrounds.

Bundle of Snakes Tutorial: Illustrator Final Result

Bundle of Snakes Tutorial: Illustrator Details

Bundle of Snakes Tutorial: Illustrator Highlights

And the Final Result

Bundle of Snakes - Final Result (Photoshop)

There you go. After adding highlights to those big black beautiful eyes, I felt like drawing a little on my tablet. The shoddy shading you see in the final image is something I manually brushed in Photoshop. Open the Illustrator file in Photoshop. Create a new layer and add a Vector Mask (Cmd+Click the “Add Mask” button in the Layers Palette). Copy and paste the orange fills from Illustrator to Photoshop. Choose “Path”. Choose a brush and shade to your liking. This way you can’t color outside the lines.

Go play.

Post edited 5 days later: used the same technique to create some drawings and icons using illustrator live tracing.

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