When working with digital images, it’s important to know which graphic file to use. Graphic files fall into two categories: raster and vector. Raster files are composed of pixels and vectors are composed of mathematical equations. Let’s take a further look at raster and vector files and their subsets.
As mentioned before, raster files are composed of pixels which can be described as a grid of single-color blocks. Another way to look at raster files is the pixels are the pieces of a jigsaw puzzle, and they come together to form an image. The nature of pixels prevents images from being resized drastically. If enlarged too much, the image will look grainy or pixelated. Raster file images can be downsized but not enlarged. The pixels enlarge to meet the image’s new size. Common raster image files include JPEG, GIF, and PNG.
JPEG stands for joint photographic experts group. It’s the standard format for compressed data because JPEG files keep a reasonable image quality despite being compressed. This allows for a large number of images to be stored with the least amount of storage space. JPEG files support 24-bit color. It’s important to note that with JPEG files, image quality decreases if a large amount of compression is used. They also can be optimized.
JPEG files are often used for photographs in web design because the small file size loads quickly. Yet, JPEG files cannot have transparent backgrounds making them not always suitable for other types of graphics. They are best used for rectangular or square photos.
GIF files are the simplest raster file available. They are composed of 256 colors making them perfect for simple graphics. It’s important to not use them on photos because of their simplistic nature.
PNG files are like JPEG but larger and are of higher quality and can have transparent backgrounds, unlike JPEG. Also, unlike JPEG, PNG files cannot be optimized.
As mentioned before, vector files are composed of mathematical equations. This allows for flexibility since vector files can be resized. Common types of vector files are EPS and PDF; PDF files can be either vector or raster files depending on the graphic. Vector files can also be converted into raster files. Remember, when working with a graphic designer always ask for a vector file.
As a vector file, EPS files can be effortlessly resized. They are good for text, graphics, and illustrations. EPS files can be reopened and edited. They are best used as master files for logos, graphics, and illustrations. It’s important to note that EPS files are compatible with newer and older versions of Illustrator.
PDF stands for portable document format. PDF files are meant for viewing, not editing. PDF files preserve document formatting making the document more shareable by looking the same on any device and allowing viewers to view the document as intended. PDF files are reliable to exchange because they can be shared independent of software, hardware, or operating system; adding to its shareability.
These are just a few examples of different types of graphic files. Many more types of graphic files exist.