What's the Difference Between .ai, .eps, .jpg, .png, and .pdf?

What the heck is a vector? I'm going to break down all of the files types I use most often, so you guys can optimize your web and social presences (and never get pixellated business cards again!)

This is a vector file opened in Illustrator. You can see the vector handles and lines (blue boxes and strokes).

This is a vector file opened in Illustrator. You can see the vector handles and lines (blue boxes and strokes).

When we zoom in, the image doesn’t get pixellated. This is a vector-based file!

When we zoom in, the image doesn’t get pixellated. This is a vector-based file!

Vector-based files:

〰️.ai (Adobe Illustrator)

〰️.eps (Encapsulated Post Script), can be opened in Illustrator or as a PDF

Vector files use math-based shapes, lines, and points to store and portray artwork, rather than pixels. You can zoom as far into a vector file as you want without pixelation! They are most commonly used for print as they are very high resolution, but are usually very large file sizes.

Pixel-based files are best for images, like this mockup of a stamp design I created.

Pixel-based files are best for images, like this mockup of a stamp design I created.

When we zoom in, the image becomes pixellated. This is how you can tell the tile is a .jpg or. png.

When we zoom in, the image becomes pixellated. This is how you can tell the tile is a .jpg or. png.

Pixel-based files:

〰️.jpeg or .jpg (Joint Photographic Experts Group)

〰️.png (Portable Network Graphics), supports transparency

Pixel-based files are most commonly used for web, as they are much smaller (compressed) and therefore don't cause websites to crash or load for a long time. They are also most likely to be lower quality because of their compressed nature. .jpeg files are lossy, meaning that they *lose* quality when you open and re-save them. .png files are lossless, meaning that they *retain* quality when opened and re-saved. If you want a high-quality image for web (that has a lot of text or sharp lines) that supports transparency, use a .png. If you need the smallest file type possible for web or social media, a .jpeg is probably the better choice.

I use PDF files most often for sharing concept presentations with my clients, as they’re easily emailed and support multiple paged documents easily.

I use PDF files most often for sharing concept presentations with my clients, as they’re easily emailed and support multiple paged documents easily.

PDF files:

〰️.pdf (Portable Document Format)

〰️.eps (Encapsulated Post Script), can be opened in Illustrator or as a PDF

PDF files were invented by Adobe in 1991 as a way to standardize the sharing of digital files across the (then very new) variety of digital devices. PDFs are so versatile because they can be high or low quality depending on destination, and if you use an Adobe program to generate a PDF, it can RETAIN ITS ORIGINAL EDITABLE DATA. This is groundbreaking, because a document you can send can be simultaneously print-ready, and also editable up to the very last minute (for those pesky typos that somehow make it into the final version).

Jen Davis