It is incredibly important for any person involved in the project management, or decision making process of creating brand materials to understand the difference between vector and raster images. Understanding these two different kinds of images will help you to:
- communicate clearly with graphic designers
- provide designers with the correct file types that they need to create high quality brand materials.
- avoid wasting time and money creating low quality brand materials that reflect badly on your business
Have you ever been scrolling through someone’s Facebook profile and come across a picture that’s so small you can barely even see what it’s of? Have you ever wondered why Facebook doesn’t just allow people to zoom in and make the picture larger? This blog will shed a light on the issue, and help you to understand the difference between vector and raster images and why it matters for your business.
Raster images are the ones you are most familiar with. Most images you see online are raster images. Any photograph taken with a camera viewed on a digital device is most likely a raster image. Photographs are made up of hundreds of colored dots. For printed images, these dots are made of ink. The closer you get to the paper, the bigger the dots get, and the worse quality the picture becomes. The same is true of raster images on a computer, but instead of ink dots you have points of colored light on your screen called “pixels.” No matter how big or small you make a raster image, the number of pixels on your screen will stay the same. When an image looks low quality or “pixelated” it’s because it has been blow up to the point that the individual light pixels are visible.
The number of pixels that make up an image is what determines its “resolution.” Raster images with more pixels or a higher resolution can be blown up bigger without becoming pixelated. Resolution is measured by the number of pixels, dots, or points per inch (ppi or dpi). The standard resolution for a raster image that is going to be printed is 300 dpi.
What are raster images good for?
Raster images work well when you know you aren’t going to be constantly resizing and repurposing an image file. Background images, blog headers, and social media images are all great uses for raster images.
Common file types
Here are the main ways that raster images can be saved:
- .jpg (JPEG) – JPEG stands for Joint Photographic Experts Group, the people that created it. These are possibly the most common file type. Most websites and digital cameras use JPEG. JPEG files are loss compressed, allowing them to be small, but this also means that they have slight color distortion and are lower quality than other file formats.
- .gif (GIF transparent file) – This is an old file type that has a limited color palette. It has an even smaller file size than JPEG and works well for small web graphics and animations.
- .png (Portable Network Graphic Transparent file) – A great option for high quality images, PNG files use lossless compression to achieve high quality resolution in a manageable file size.
- .tif or .tiff (Tag Interleaved File). – TIF files are considered the most high quality and versatile file type. They are often used for commercial purposes. The main drawback of TIF files is that web pages cannot display them.
- .psd (Photoshop Shop Document) – Adobe Photoshop is a graphic design program designed to work with raster files. A .psd file is a saved photoshop project and usually consists of a bundle of raster images. These files can only be opened by Adobe Photoshop.
- .pdf (Portable Document Format) – PDFs are a versatile file type that can contain raster or vector files. PDFs are often used for printing documents such as pamphlets and books.
Vector images, unlike Raster images are infinitely scalable. While raster images are made up of pixels, vector images are made of paths controlled by mathematical formulas. When you expand a vector image or zoom in, instead of expanding a fixed number of colored dots, your screen keeps all the dots the same size and just adds more to make up the image. This allows you to expand vector images as much as you want without ever losing any quality.
What are vector images good for?
Since vector images never lose quality, they are great for designing images that will be reused and resized such as logos, signage, and illustrations. In fact if your business doesn’t have a vector file of your logo, that is a huge problem! Before long, you’ll notice your raster logo looking pixelated and low quality on your branding materials.
Vector files are best used for the creation and editing of images. For example, you would have your your company logo created as a vector file, but if you wanted to put your logo on your website and on the side of a truck you would make a .jpeg or .png copy of your vector logo for website and save a large .pdf of your logo to put on the side of the truck.
Common file types:
Here are the main ways that raster images can be saved:
- .eps (Encapsulated PostScript) – Probably the most common vector file type, it is the standard file type for the print industry. This file type is compatible with most programs.
- .ai (Adobe Illustrator) – The native file type for Adobe’s Illustrator program. Illustrator is the most common program used to create and edit vector files.
- .svg (Scalable Vector Graphics) – The W3C standard vector image format. Adobe Illustrator and CorelDRAW both support SVG files.
- .dxf (Drawing Exchange Format) – This is a vector file format used for CAD drawing in Autodesk.
- .pdf (Portable Document Format) – This is the only file format that can support both vector and raster images. For this reason, you can’t assume that a file is vector or raster if it’s a PDF file.
Here’s a quick video to help you better understand the difference between vector and raster:
Being aware of the different strengths and weaknesses of vector and raster images, and the different file types that they come in will help you to communicate well with your graphic designers, get them the files they need, and avoid headaches with low quality brand imagery that can reflect poorly on your company.