If you work with images often, you may have encountered the terms "raster" and "vector." Or you may have worked with a designer who has requested a vector file type. But what the heck are they, and why do you need to know about them?
What is a raster image?
Raster images (also known as bitmap or pixel-based photos) are made up of tiny squares called pixels. Think of it like a mosaic, where each tile is a different colour. If you zoom in on a raster image, you can see these individual pixels.
A raster image at large scale
There are only a certain amount of pixels in an image, so if scaled too large, the image becomes distorted or ‘pixelated’.
Images on websites are particularly small ‘rasters’ and can’t be used for print purposes.
Common raster image file types include:
- JPG (JPEG)
- PNG
- GIF
- TIFF
Raster images are great for photographs with lots of detail and colour gradations. However, they have some limitations. Because they consist of pixels, they can lose quality when resized, especially when enlarged.
What is a vector graphic?
On the other hand, vector files (sometimes called object-oriented graphics or line art) are created using lines and curves and can be scaled to any size without losing quality.
A vector image at large scale
Common vector image file types include:
- AI (Adobe Illustrator)
- EPS (Encapsulated PostScript)
- SVG (Scalable Vector Graphics)
- PDF (Portable Document Format) Note: rasters can be saved as PDFs, too. So, if you save a JPEG logo as a PDF, it won't automatically become a vector.
Vector files are ideal for logos, illustrations, and graphics that need to be resized or used in different contexts. They're also great for creating sharp, clean lines and shapes.
Side note: logos and vectors
Vector-based images are the industry standard for logos. This is because they can be scaled to any size without losing quality, ensuring your logo looks sharp and professional on a business card or a billboard.
Why it matters
Using the correct image type can ensure your brand looks its best – particularly in print. If your designer has requested a vector logo, it's often because what you've provided isn't up to snuff for the printed environment. Just because a file looks okay on screen doesn't mean it will print well. Sourcing the correct file can mean the difference between your logo appearing crystal clear and a pixelated print disaster!
Vector files are best-practice for logos in the digital world, too. Vector files are usually smaller file sizes, which can improve website loading times and reduce storage space, and they'll maintain their crispness on high-resolution screens.
How can you tell if an image is a vector or raster?
A quick way to tell if an image is vector or raster is to zoom in on it. If you see pixels, it's a raster image. If the image remains smooth and crisp, it's likely a vector image. You can also check the file type. If it's a JPG, PNG, GIF, or TIFF, it's a raster image. If it's an AI, EPS, SVG, or PDF, it's likely a vector image.
Can I turn an raster logo file into a vector logo file?
The short answer is no, or at least not easily or precisely. Some software provides image tracing capabilities but these are generally not accurate and can produce messy results. The best option is to contact the designer who originally created your logo - they can provide you with an .eps or .ai file. A second option is to get a designer to recreate your logo in vector format for you.
By always using the right image type, you'll ensure your brand and images always look their best, in print and on screen.
Need help optimising creating a vector version of your logo? Book in for a free consultation.
