What is a vector file?

Learn about vector files, their function and file formats, and what software uses them to expand your understanding of this diverse file type.

Abstract and colorful digital illustration saved as a vector file.

Vector files: Useful in many different environments.

When you’re working digitally, there are two kinds of image file types: raster and vector. Both image types may be saved with several different file extensions. It’s important to understand when to use each image type and the best file extension for particular situations.


What is a vector image?

Vector files are images that are built by mathematical formulas that establish points on a grid. Raster files are composed of the colored blocks commonly referred to as pixels. Because they can infinitely adjust in size without losing resolution, vector files are more versatile for certain types of tasks than raster files. The most common types of vector files are:

 

.ai: Short for Adobe Illustrator, this file is commonly used in print media and digital graphics, such as logos.

.eps: Encapsulated PostScript is an older type of vector graphics file. .eps files don’t support transparency in the way more modern file formats like .ai do.

.pdf: The Portable Document Format is built for the exchange of documents across platforms and is editable in Adobe Acrobat.

.svg: The Scalable Vector Graphics format is based in XML (a markup language used widely across the Internet that's readable by both machines and humans). It’s useful for the web, where it can be indexed, searched, and scripted.


It’s worth remembering that there are different resolution requirements for web or print – and this may affect how large your vector file needs to be.

 

The ideal image resolution for web is 72 dots per inch (dpi). Any larger and the images will take too long to load. This is a much lower resolution than what would be recommended for print, which would be at least 1600 x 1200 pixels for a 16x12-inch print.

 

What is a raster file?

Raster files are composed of coloured blocks commonly referred to as pixels. Comprising a fixed number of pixels, raster images can’t be resized significantly without losing some of their resolution quality. Images distort and become grainy when stretched to fill a larger space, which is why they can appear pixelated when resized. Common types of raster files include:
 

.jpg: A compressed image format standardised by the Joint Photographic Experts Group (JPEG). This is the most commonly used format for digital and online photos.

.png: Images saved in the Portable Network Graphic (PNG) format have the ability to display transparent backgrounds.

.gif: The Graphic Interchange Format (GIF) file extension is used for animated graphics. This is the second-most used image format online. 

.tif: Images saved as a Tagged Image Format File (also TIFF) are popular with photographers and graphic designers as they can be edited and re-saved without losing image quality.

Example of the smooth and defined quality of a vector file.

Vector file.

Example of the rough pixelation of a raster file.

Raster file.

When to use vector files.

The key difference between vector and raster files comes down to utility. Raster files are composed of a set number of pixels. Because of this set number, if a raster file is printed at a larger dimension than what it was designed for, it will appear visibly grainy and pixelated because the dots that compose the image are forced to grow larger as the medium they’re printed on grows. In other words, don’t print an image from Instagram at poster size and expect it to look as crisp as it did onscreen. 

“The key difference between vector and raster files comes down to utility.”

Since vectors are based around formulas, vector graphics can scale at high resolution to virtually unlimited sizes. If you have a business logo saved in a vector format, it can be resized to fit on a billboard with no problems or reduced to be printed on a ballpoint pen or business card. Many printing processes can only work with vector file input. 

“Since vectors are based around formulas, a vector image can scale at high resolution to virtually unlimited sizes.”

Do I need a vector file for my logo?

A vector file is often the best format for a logo. Many production companies require high resolution files and will request your logo as a vector. This is because a vector image comes in the same clarity whatever size is required – whether it’s being printed on a massive billboard, the front of a mug or simply on an A4 poster. 
 

How do I convert a file to vector format?

When creating an image in Adobe Illustrator, you can automatically save it as a vector file. You can also use Adobe Capture to convert photos into a vector format. To manually convert a file into a vector format in Illustrator, follow these steps:
 

  1. Open Adobe Illustrator and select the Tracing workspace in the top right-hand corner.
  2. Add your image from the file menu or drag and drop it, then select it to activate the Image Trace panel.
  3. Check the Preview setting and try one of the pre-sets in the Image Trace panel (such as auto-colour).
  4. Adjust the colour complexity with the colour slider – converted vector images don’t always show well in all their natural colours.
  5. Open the advanced section of the Image Trace panel and use the Paths, Corners and Noise functions to form a smoother image.
  6. Click Trace when you’re finished.
  7. When the tracing is complete, click Expand – this replaces your .jpg with the vector image.
  8. Export your image as a vector file, saving as a .ai file first so you can go back in to make more edits if necessary.

How can you tell if an image is a vector file?

One quick way to tell if an image is a vector file is to look at the extension. If it’s saved as .jpg, .png, .gif or .tif, it’s a raster file. When it’s saved as a .ai, .eps, .svg or .pdf, it’s a vector file.
 

Alternatively, you can visually check by enlarging the image on your computer, phone or tablet screen to around 200% or higher. If the edges blur and the colours appear in different shades, then you have a raster image. Should the edges remain clean and the colours solid, then it’s a vector image. 
 

Editing vector files in different applications.

The most common type of editable vector file is the Adobe Illustrator (.ai) file. This file type can store an enormous amount of graphics information and is editable in Adobe Illustrator. Illustrator files can be easily converted to .pdf. Adobe Acrobat is the best tool for editing .pdf documents, which are designed for both printing and document transfer. Many printers utilise .pdf as a standard for printing. The work you do in an Illustrator file is non-destructive, so conversion to the .pdf format is usually a last step.

 

The best way to edit and create vector files is in the Illustrator environment — start exploring it with the Adobe Help Centre.

Saving a design as a vector file format in a vector graphics software program.

Explore vector images from Adobe Stock.

Find the perfect vector images. Discover vector logos, characters, backgrounds and more on Adobe Stock.

 

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