Live Trace

Tracing in Illustrator

Open a document in Illustrator and place your clean PSD image. Click on the image to select. Click the small box to the right of the Live Trace button called Tracing Presets and Options and scroll down to Tracing Options.

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The Tracing Options dialogue box will open. There are many preset selections to choose from but we’re going to use our own settings to get the best possible trace:

  • Check Preview: Now you can see the effects live as you change the settings.
  • Check Ignore White: Now the white background is not present.
  • Set the Mode: Select Black and White. Leave Raster set to No Image and Vector set to Tracing Results, and check Fills.

Since you can see the results live, it helps to play with the settings a bit to get used to what effect they have. The way to think of the settings is that the left side (Adjustments) resembles Photoshop, and is conditioning the raster image before it is traced; the right side (Trace Settings) resembles Illustrator, and is taking the conditioned rasterized image and converting it to paths. Let’s look at what the most relevant settings do.

  • Threshold: This value determines which pixels are white and which are black. Any pixels lighter than the Threshold value are turned white and all pixels darker will become black. For instance, making the threshold higher means that more of the darker pixels will be included in the vector shape.
  • Blur: This blurs the original image before its traced, which helps smooth out jagged edges.
  • Resample: This may come as a surprise to some, but with Live Trace, a higher resolution doesn’t necessarily translate to a better traced result. In many cases, a high-resolution file can add unwanted complexity to a traced file. So play with this feature to see if your image might do better using a lower resolution.
  • Path Fitting: The lower the number/setting, the tighter the image will be traced. If it’s too low you could get a jaggy effect. The higher the number/setting, the smoother the effect, but you lose detail.
  • Minimum Area: Defines the minimum area that will be traced, which helps get rid of the imperfections or “dirty” areas you don’t want to capture. This setting determines the pixel minimum area, so anything smaller won’t be traced.
  • Corner Angle: Sets the sharpness of the corner angles. The lower the number/setting, the sharper the corners.

When you are happy with the settings, be sure to first Save Preset. This is on the right of the Tracing Options dialogue box and will come in very handy if you need to make some other changes before tracing again. Once you’ve saved, hit Trace. You will then need to hit the Expand button or Object -> Live Trace -> Expand to see the actual results.

Edit and Tweak the Results

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SEPARATE GROUPED VECTOR OBJECTS

Be sure to Ungroup (Shift + Cmd/Ctrl + G) (Object > Ungroup) as many times as necessary to make sure everything is ungrouped.

In the above images you can see that I did some editing to my original trace. Some shapes were unwittingly grouped together, despite my efforts in Photoshop to keep them separate. Luckily, should this happen, there are a few easy solutions.

Revise the Original Image:

It is easy to go back and quickly edit your image in Photoshop with a click of a button. The Undo (Cmd/Ctrl + Z) command will need to be applied until you return to the raster image (hence saving the preset, so we can use it again here):

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Go to the Links panel (Window > Links) and click on the little pencil icon in the lower right corner. It can now be instantly edited in Photoshop. When the editing is done, close the window and when prompted, choose to update/save the changes in Illustrator. You can now use your preset to re-apply the trace in Illustrator.

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Use the Knife Tool:

Another solution is to simply use the Knife Tool (pictured above, it is part of the Eraser group on the tool bar) to cut grouped anchor points apart. It helps to View Outlines (Cmd/Ctrl+Y). You can also hold down Alt to have the knife tool cut a straight line. Zoom in by scrolling while holdingCmd/Ctrl. The Delete Anchor Point Tool (Pen Tool + minus sign) is another tool for deleting anchor points and separating grouped objects.

Live Paint (see “Inspirational Suggestions” section below):

This feature doesn’t actually alter any of the vector groupings; instead it allows the coloring and texturing of any lines or shapes, regardless of how they are grouped.

REDUCE THE NUMBER OF ANCHOR POINTS

Live Trace tends to produce an extraneous amount of anchor points in some places. To get rid of some of these we can use the Smooth Tool (pictured in the above image). Click and drag to simplify and reduce the anchor points and to smooth curves.

TOUCH-UPS

If some shapes did not trace properly (as with the circles in the example below), they can quickly be redrawn. It’s helpful to lock down the original raster art on the background at around 20% opacity.

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Final result.