Rasterize: Turning Vectors into Rasters


It's easy to see the benefits of converting raster images into vector-based artwork to allow for better scaling and editing. Interestingly enough, Illustrator can also perform the transition in reverseconverting vector-based artwork into rasterized art. Sometimes this is done to achieve a special effect where you might want to see a pixilated image (Figure 8.28). Alternatively, you might start with a gradient mesh object, which you then rasterize and then convert back to vectors using Live Trace to achieve a posterized graphic effect (Figure 8.29).

Figure 8.28. Rasterizing text at an extremely low resolution can add an interesting design element to your layout.


Figure 8.29. Once you've rasterized a gradient mesh object (left), performing a Live Trace can produce abstract design elements (right).


To convert vector artwork to pixels, select the art and choose Object > Rasterize, which brings up the Rasterize dialog. You'll find that there are a variety of different settings from which to choose when rasterizing artwork (Figure 8.30).

Figure 8.30. The Rasterize dialog should look familiarit's nearly identical to the Rasterize Effect dialog.


If your artwork contains spot colors, the Rasterize effect converts those colors to process equivalents. To prevent this from happening, you should use the Rasterize Live Effect instead (refer to Chapter 7, 3D and Other Live Effects).



  • Color Model. Depending on the document color mode setting to which your file is set, you'll either see CMYK, Grayscale, and Bitmap listed here, or you'll see RGB, Grayscale, and Bitmap. This is because a document cannot contain both CMYK and RGB elements. This setting can be extremely useful, because it allows you to change the color model of an object (even an image). For example, you can convert colored objects to grayscale.

  • Resolution. Here in the Rasterize dialog, the default resolution is set to 300 ppi, which is usually sufficient for print-related artwork. If you want all of your artwork in your document to appear consistent, you can also specify that the resolution setting should match the setting found in the Document Raster Effects Settings dialog.

  • Background. You can choose whether the resulting raster will have a transparent background or a white background. If your effect overlaps other objects, you probably want to use the transparent setting, although remember that the file still needs to be flattened (see Chapter 11, Prepress and Printing, for more information on transparency flattening).

  • Anti-alias. You can define whether or not the raster image will be anti-aliased. Anti-aliasing slightly blurs color boundaries to avoid the appearance of jagged edges. For more information on anti-aliasing, refer to Chapter 10, Illustrator and the Web.

  • Create Clipping Mask. Creates a clipping mask around the area of a shape so that you can have it blend into a background (raster images are always rectangular in shape and may block out objects that appear behind them). This setting won't work very well for objects that have Drop Shadow, Feather, or Glow effects applied, because clipping masks have hard edges. This setting is not necessary if you specify the Transparent option for the Background.

  • Add Space Around Object. Depending on the kind of artwork that you are rasterizing, you may experience some clipping when the artwork becomes rasterized. This is especially possible when rasterizing objects that have soft edges, like Feather effects, applied. Specifying extra space around the object results in a larger raster image, but that incorporates all of the artwork.




Real World Adobe Illustrator CS2
Real World Adobe Illustrator CS2
ISBN: 0321337026
EAN: 2147483647
Year: 2003
Pages: 147
Authors: Mordy Golding

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