Raster and vector images are completely different but each perfect for its intended use. Designers typically use each file type everyday. Here’s a list of their basic differences and how to use them best.
An image made of pixels — millions of them. Each pixel has a single color, and its information is recorded in the image file.
Art with complex blends of detailed color
gif, tiff, jpeg, png, bmp, psd (Adobe Photoshop’s own format)
• Rasters are good at showing complex detail and gradiation like color blends.
• Raster file formats let you edit each pixel separately, if so desired.
• Enlarging files makes the images blurry or grainy (pixellated)
• A raster image at standard 300 ppi printing resolution will have 300 pixels per square inch. For full-page or larger printing, a high-quality raster image can have a dramatically large file size. This means you also need a fast, strong (read “expensive”) computer to handle these files.
• Smaller raster file formats (like jpegs, pings and gifs) are flattened files. Any editing you want to do to them has to be started from scratch.
However, standard vector eps or ai files imported into Photoshop are flattened automatically and can’t be edited.
Also, if one of Photoshop’s smart objects is saved in a flattened raster format, it will no longer be editable or scalable. It becomes a standard raster image file.
An image made of lines connected with points to form angles or curves. If the lines make closed shapes, these can be filled with color or a simple gradient. The points, their angles, and the optional color is recorded in the image file.
Clean art without complex color blends that is intended to be enlarged and reduced frequently.
e.g. logos and fonts
eps, pdf, ai (Adobe Illustrator’s own format)
• You can enlarge or reduce a vector virtually as much as you want without losing quality.
I’ve designed vector graphics saved in eps files at 3 inches x 12 inches to be reproduced for banners 3 feet wide x 12 feet high. The printer was happy with my files, and the banners looked great.
• Vectors file formats are relatively small because they only includes each point, its angle, and its optional color fill.
• Vector files are never flattened and so a copy is equally as editable as an original file.
• Vectors have limited color matching, especially in gradients
• Image effects like drop shadows or blurs can’t be reliably used. Some of these effects are available in vector programs like Adobe Illustrator, but the effects are still raster-based and will be affected when you resize the file.
These two types of image files are not interchangeable but they’re each great at their own purposes. Most designers favor one above the other, but learning to use both raster and vector files makes you quicker and more capable at producing the design products your customers may need.