Editing Raster in Illustrator
One thing I always caution people on when working with raster in Illustrator is to be careful with scaling. Like in InDesign, Illustrator believes in garbage-in, garbage-out. If the image you place in Illustrator is too small or too low resolution, it most likely won’t look good. Scaling images larger means lowering the effective resolution. For instance, if you place an image that is 2 inches in width at 200 ppi, and scale it to 200%, the image will become 4 inches in width at 100 ppi. Be careful and try not to scale images up (down is usually okay to a point).
You can always see what resolution the image is in the Links panel or in the Control panel (like I mentioned previously).
In Illustrator, you can also apply artistic effects called “Photoshop effects.” These types of effects are found in the Effect menu in Illustrator and are labeled as Photoshop effects. Using these effects, you can do things like blur images or apply artistic effects like film grain (see Figure 10). Just know that applying a Photoshop effect rasterizes artwork, unless it’s already a raster image.
Figure 10 Photoshop effects we can apply
Another great feature of Illustrator when it comes to raster images is colorizing. If the image is embedded (it must be to do this), you can select the image and choose Edit > Edit Colors and you can choose an option for editing the color of an image. Depending on the color mode of the image (RGB vs. CMYK), some options may not be available. I love this because you can make color adjustments on the fly that don’t affect the original image you placed (the image is embedded at this point). You can convert an image to grayscale or adjust its CMYK (or RGB) mix (see Figure 11).
Figure 11 Editing the color of an image
Unfortunately, if you need to edit the raster image (changing its levels, sharpening, etc.), you will need to head over to Photoshop or another image editing tool and do it there. As I mentioned previously, this is pretty easy to do if you the image is linked and can then be updated in Illustrator.