When you import artwork from an Adobe PDF file, it’s possible to introduce data that you can’t create within Illustrator. This is called non-native art and includes monotone, duotone, and tritone images. You can also generate non-native art within Illustrator by using the Flatten Transparency command to preserve spot colors.

Illustrator’s ability to preserve non-native art is useful in many situations. For example, Illustrator maintains the spot color information in linked PDF files when you output color separations.

By default, non-native art is labeled <Non-Native Art> in the Layers and Appearance panels. You can select, move, save, and perform basic transformations (such as scaling, rotating, or skewing) on non-native art. However, you cannot select and edit its individual components. In addition, you must rasterize non-native art before editing it with the liquify tools.

To convert non-native art to an Illustrator object, choose Object > Rasterize.