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When working with graphic design and print, it’s important to understand the difference between vector and raster images. Each type has its strengths and use cases, so knowing how to identify them will ensure your designs look sharp and professional, no matter how big or small.
Vector Images
Vector images are made of lines, curves, and shapes that can be resized infinitely without losing quality. Whether you are shrinking or enlarging the artwork, the edges will stay crisp and sharp with no pixelation.
Common vector file formats include AI, SVG, and EPS.
To check if a file is a vector, zoom in as much as possible. If the edges remain sharp, it’s a vector. If the image starts to get pixelated, it’s likely a raster image.
Raster Images
Raster images are composed of pixels, and image quality is tied to resolution. Meaning they degrade in quality when scaled beyond their native resolution. The more you enlarge them, the more pixelated and blurry they become.
Common raster file formats include JPEG, PNG, and BMP.
How to Check Your Vector Files Without Illustrator
You don’t need Adobe Illustrator to check your files. Here’s how:
- AI, EPS, and PDF files can be opened with Adobe Acrobat or any PDF reader. Zoom in by pressing the ‘+’ button at the top or holding down ‘Ctrl’ (or ‘Command’ on Mac) and pressing ‘+’ repeatedly.
- SVG files can be opened in any browser. Simply zoom in by holding ‘Ctrl’ (or ‘Command’ on Mac) and pressing ‘+’ repeatedly.
If the image looks pixelated, it probably means the file was exported at a lower resolution, which converted the artwork to a raster image, or that a raster image was incorrectly converted to a vector file.
Checking Resolution of Raster Files
To check the quality of a raster file, look for its resolution in the file information. For raster images, PPI (Pixels Per Inch) refers to digital display resolution, and DPI (Dots Per Inch) refers to print resolution. These are always the same, though, so if an image is 300 PPI, it’s also 300 DPI, which is the ideal resolution for high-quality prints.
To check the resolution of JPEG, PNG, or BMP files, open them in the Windows or Mac photo viewer. Then, locate the ‘more information’ tool to see the file size and resolution.
Also, make sure the image is set to 100% zoom (you’ll usually see this at the bottom of the screen) to view it at full scale. This shows the largest size the image can be printed without degrading quality.
Notable Mention: Bitmap Files
Lastly, it’s important to mention the Bitmap (BMP) file format. These files are intended to have low resolution and are intentionally pixelated. They are often used for pixel-style graphics, such as retro video games.
Conclusion
Vector files are ideal for scalable designs, such as logos, icons, and sharp illustrations; raster images work best for photos and realistic artwork with a fixed resolution. By zooming in and checking the resolution, you can easily identify which file type you’re working with and ensure your designs are print-ready.
