Understanding Vector Graphics in Illustrator
In general, there are two types of files: vector and raster files. Raster files use pixels where as vector files have distinct lines and shapes. Adobe Illustrator serves as an editor for vector graphics while also housing many of the tools and capabilities of other Adobe programs. Vector graphics use mathematically defined points, lines, and shapes rather than pixels. This allows graphics created as vectors to be expanded or enlarged without compromising the quality or clarity of the image/graphic as it goes from large to small sizes.
Since the program supports editing of vector graphics, the application is typically used to create logos, graphic icons, or any other files that may be enlarged or manipulated. Illustrator makes it easy to edit the lines and shapes that make up the vectors and offers multiple file saving formats to ensure the files can be edited in the future (unlike any type of raster file).
“Vector files such as AI and EPS can remain editable so you can open them back up in Illustrator and edit any text or other elements within the graphic. With images that contain text that are saved as a JPG, PNG or GIF, you would not be able to reopen and edit the text.”
The four types of vector files that Illustrator supports are as follows: .AI, .PDF, .ESP, and .SVG. Each format has its own benefits as well as downfalls. Other common file formats, such as JPG, PGN, and GIF, are raster files that use pixels.
First, the AI file format was created by Adobe for Adobe products. AI files are only created in Adobe programs and can only be opened through them as well. The main advantage of using AI or ESP files is that it allows the files to be saved in a format that will account for further editing. This is done by making a master file using these file formats and saving specific JPG, PNG, or GIF format when needed.
“Since most vector files require special applications to open, master files are saved as a ESP file and other versions of that file are then saved as JPG, PNG, etc. The master ESP file can then be edited further later on.“
Though it can technically be considered a vector file, the only way a PDF file can be a true vector file is if it were originally created as one.
Last but not least, SVG files are scalable vector graphics. Most website graphics are created and saved using this format because it also allows the files to be resized without compromising quality. These types of files can also be compressed.
Illustrator’s sole purpose is to create and edit vector images and graphics. However, due to the incredible functionality of the program, it is able to host similar tools and editing options that are typically found in Photoshop – to include the ability to edit files and graphics that are saved in a raster format. In contrary, even if files are created as vector graphics, it might be better suited that they are transformed or saved in a raster format. For example, files or graphics that will be used online are better suited, generally, as raster files. On specific of this situation might be the fact that Even though a PNG file is a raster rather than a vector file, most logos or graphics are saved in their format because it allows for a transparent background.