What Does Rasterize Mean In Adobe Illustrator?
To Rasterize in illustrator means to convert a vector graphic, which is made up of paths and anchor points, and converting it into a raster image, made of pixels. Vector graphics are visual representations of mathematical formulas and are easily manipulated using the tools available in Adobe Illustrator and do not lose quality with enlargement.
Raster images are like jpgs and pngs; they are best suited for pixel-based editing software like Photoshop. These images lose quality when enlarged. If you zoom into a vector on Illustrator, the edges and lines remain sharp, but if you zoom in on a rasterized image, the edges become jagged or pixelated.
Should you rasterize objects in Illustrator?
Rasterizing objects in Illustrator is mostly done when you need to open a vector graphic with a program that doesn’t support vector images, therefore you rasterize it to convert it into a jpg or png. However, Illustrator has export features that allow you to save and share your images as rasterized/bitmap images once you are done working, so there’s rarely ever a need to rasterize your work on Illustrator before you are done with it.
Rasterizing is also hard to reverse especially if your vector is very detailed and you rasterized it in low quality. If you need to export your vector to Photoshop, you don’t need to rasterize it in Illustrator. You can just copy and paste it into Photoshop and you’ll have the option to convert it there or work with it as a smart/linked object.
Another reason for rasterizing in Illustrator is when working with text. You may rasterize text in Illustrator so that when you share the design to a computer that doesn’t have the specific font, the person may still be able to view the text object.
However, if you use this method, the text will become pixelated and lose quality if enlarged. The best way to go about it, rather than rasterize the text, is to expand the text object in Illustrator which will turn it into a vector outline. It will not be editable as a text anymore, just as when you rasterize it, but as a vector, the text won’t lose quality when enlarged on screen or in print.
How to rasterize in illustrator without losing quality
To rasterize a vector in Illustrator without losing quality:
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- Select the vector or text you want to rasterize using the selection tool (v). Hold down shift as you select if you want to rasterize several objects into one image. The dimensions of your objects on your artboard are the dimensions they will rasterize to. Therefore if you transform them to a larger size before rasterizing, you will get a higher resolution image.
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- Copy your vectors on another artboard, file, or hidden layer. This is so you can access them as vector files later if you need to. The rasterize process is permanent and irreversible once you’ve saved your file.
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- Go to Object>Rasterize…
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- A window will pop-up with the rasterize options. Select the color mode you want your rasterized object to have. The default will match your original document color mode. So if you set it up as CMYK, the default will be CMYK. The same goes for RGB. You will have two other options in either scenario; Grayscale and Bitmap.
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- Choose your resolution. 300 PPI is best for printing purposes and 72 PPI is best for viewing on screens and sharing online. You can choose “other” if you wish to set your own specific resolution. “Use document raster effect resolution” will match your rasterized image’s resolution to that of your working document.
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- Choose whether you want a white background or a transparent one. These don’t affect your image’s final quality.
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- Select the best anti-aliasing option for you. Anti-aliasing smooths out and blurs rough edges by adding pixels around the edges and color boundaries when rasterizing your image. (see below)This prevents your curves and diagonals from looking jagged and unnatural. If you select “None“, the edges will be crisper but curves or diagonal lines will appear jagged. (see image below)“Art optimized” anti-aliasing will add this effect to your shapes but is not recommended for texts. “Text-optimized” is best suited for rasterizing text to the best quality. You can play around with these settings and undo the raster if you don’t like the result.
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- Leave the other settings as default and click “Ok”. Your object is now rasterized.
If you don’t notice any difference, that’s a good sign that your image has rasterized in high quality. If you zoom in you’ll notice the pixels. Your rasterized image won’t have paths and anchor points like vector objects.
Illustrator is a vector-drawing application, but it also supports display of bitmapped images. When you rasterize an object in illustrator, you’re converting from vector to bitmapped and losing all of the vector information. Example:
This is a screen capture showing a vector star on the left, raster on the right. They look pretty much the same until you scale them or zoom in, but the biggest difference is when you switch to outline view:
Rasterized images are now just a box, because the object area has been converted to bitmap. Why would you do this? Possibly to map the raster image onto a 3d surface, or to reduce the complexity of a detailed illustration. I rarely use this feature because you can also rasterize images on export or in Photoshop, but it’s nice to have just in case you don’t want to make the round-trip outside of illustrator.
