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Working with Live Trace
There are times when it may be ineffi cient to draw complex illustrations by hand if a suitable raster version exists. At times like this, it may be better to simply scan the original artwork and use the Live Trace feature in Illustrator to have the application convert it into vector art for you.
Using the tracing presets
The Live Trace feature in Illustrator comes complete with various presets for rendering a wide variety of artwork into vector form.
1 Choose File > Open. In the Open dialog box, navigate to the ai05lessons folder and select the ai0504.ai fi le. This is a practice fi le containing an embedded JPEG graphic that you will modify in the following exercises.
Choose File > Save As. In the Save As dialog box, navigate to the ai05lessons folder and type ai0504_work.ai in the Name text fi eld. Press Save.
2 Choose the Selection tool ( ) from the Tools panel and select the butterfl y image. Locate the Live Trace button in the Control panel at the top of the workspace.
3 Press the arrow next to the Live Trace button and select Hand Drawn Sketch. This option renders the entire drawing as lines and is not suitable for this image, as it would eliminate the wide range of line weights used in the original drawing.
The Live Trace Preset Options.
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4 Select the Inked Drawing preset from the Preset drop-down menu to have the program retrace the image with new settings. This is better, but several of the spots on the bottom wings vanish and the lines don’t seem to match up with each other.
The image shown using the Inked Drawing preset.
5 With the image still selected, select the Comic Art preset from the Live Trace drop-down menu to have the program retrace the image with new settings. This preset seems to more closely match the artwork than the two previous choices.
The image shown using the Comic Art Live Trace preset.
Even the best of presets are guesses for what will probably work well with the provided type of artwork. For more control over the conversion, you can tweak the preset in the Tracing Options dialog box. Working with the Tracing Options dialog box is covered in the next section.
6 Choose File > Save to save your work.
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Understanding tracing options
While the Tracing presets often produce acceptable results, the Tracing Options dialog box allows you to determine the specifi c settings for the tracing of a particular object.
1 With the traced image of the butterfl y still selected, press the Tracing Options button ( ) next to the Preset drop-down menu in the Control panel to open the Tracing Options dialog box.
The Tracing Options dialog box.
2 The Tracing Options dialog box is divided into four diff erent sections: Preset, Adjustments, Trace Settings, and View.
Preset: This drop-down menu is used to select which preset’s options to display in the dialog box.
Adjustments: This controls the options that govern what happens to an image before the tracing operation is performed, as well as how colors are handled after the operation.
ADJUSTMENT USE
Mode Specifies a color mode for the tracing result. The choices in this menu are Color, Black & White, or Grayscale.
Threshold Specifies a value for generating a black-and-white tracing result from the original image. All pixels lighter than the Threshold value are converted to white, while all pixels darker than the Threshold value are converted to black. (This option is available only when Mode is set to Black and White.) Palette Specifies a panel for generating a color or grayscale tracing from the
original image. (This option is available only when Mode is set to Color or Grayscale.) To let Illustrator determine the colors in the tracing, select Automatic. To use a custom panel for the tracing, select a swatch library name. The swatch library must be open in order for it to appear in the panel menu.
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ADJUSTMENT USE
Max Colors Active only when the Color or Grayscale option is selected in the mode menu and when the Palette menu is set to automatic. The Max Colors menu is used to specify the maximum number of colors that will be rendered in the tracing result.
Output To Swatches
Creates a new swatch in the Swatches panel for each color in the tracing result.
Blur Blurs the original image before generating the tracing result. Select this option to reduce small artifacts and smooth jagged edges in the tracing result.
Resample Resamples the original image to the specified resolution before generating the tracing result. This option is useful for speeding up the tracing process for large images but can yield degraded results.
Trace Settings: This controls the setting for the tracing operation.
SETTING USE
Fills Creates filled regions in the tracing result.
Strokes Creates stroked paths in the tracing result.
Max Stroke Weight Specifies the maximum width of features in the original image that can be stroked. Features larger than the maximum width become outlined areas in the tracing result.
Min Stroke Length Specifies the minimum length of features in the original image that can be stroked. Features smaller than the minimum length are omitted from the tracing result.
Path Fitting Controls the distance between the traced shape and the original pixel shape. Lower values create a path that is closer to the original pixel shapes, while higher values create looser-fitting paths.
Minimum Area Specifies the smallest feature in the original image that will be traced. The value for this property is based on the overall area of the objects being traced.
Corner Angle Controls the sharpness of a turn in the original image that is considered a corner anchor point in the tracing result. For more information on the difference between a corner anchor point and a smooth anchor point, you should review the sections on working with anchor points and drawing with the Pen tool earlier in this lesson.
View: This controls how the original bitmap image and vector result are displayed on the artboard.
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3 In the Tracing Options dialog box, press the arrow next to the Threshold text fi eld and change the value to 50. This changes the black and white balance of the traced image and makes the spots on the lower part of the wing more distinct.
4 Highlight the value in the Path Fitting text fi eld and type .5 px.
5 Changing any setting in the dialog box, as you have done here, creates a custom tracing preset. To save this preset for later use, press the Save Preset button.
6 In the Save Tracing Preset dialog box, type Modifi ed Comic into the Name text fi eld and press OK. Press Trace to trace the butterfl y image.
7 Choose File > Save to save your work.
Expanding Live Traced artwork
You may have noticed by now that even though you can change the tracing setting of the image, you don’t have access to the anchor points that make up the new vector artwork. This is because the tracing is a type of intermediate stage between the original raster graphic and the fully editable vector artwork that Illustrator typically creates. To make the live traced artwork fully editable requires that you expand it.
1 With the traced image of the butterfl y still selected, press the Expand button in the Control panel. The paths that make up the traced artwork are now fully editable.
2 When the original bitmap was traced, the white background became a shape. This can cause a problem, as you probably don’t want a white frame around your vector artwork.
Choose the Direct Selection tool ( ) from the Tools panel and click the artboard to deselect all objects, then click to select the white area behind the butterfl y.
The white shape is selected.
3 Press the Backspace (Windows) or Delete (Mac OS) key on the keyboard to remove the white from the artboard, leaving only the butterfl y tracing itself.
4 Choose File > Save to save your work.
Another way to avoid including white objects when you trace bitmap objects is to choose the Ignore White checkbox in the Live Trace settings window at the time you start the Live Trace.
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