PHOTOGRAPHY
When working with digital photos, graphic design, logos and other digital images, raster and vector are the two most common file types you’ll encounter. Learn about the key features, similarities and differences between the two to decide when and where to use each.
Raster files are images built from pixels — tiny colour squares that, in great quantity, can form highly detailed images such as photographs. The more pixels an image has, the higher quality it will be, and vice versa. The number of pixels in an image depends on the file type (for example, JPEG, GIF or PNG).
Vector files use mathematical equations, lines and curves with fixed points on a grid to produce an image. There are no pixels in a vector file. A vector file’s mathematical formulas capture shape, border and fill colour to build an image. Because the mathematical formula recalibrates to any size, you can scale a vector image up or down without affecting its quality.
Raster and vector files are the two most popular formats used for visual content. They represent images in very different ways, so there’s a lot to consider when deciding which one to use. Some of the main differences between raster and vector include:
One of the main differences between raster and vector files is their resolution. The resolution of a raster file is referred to in DPI (dots per inch) or PPI (pixels per inch). If you zoom in or expand the size of a raster image, you start to see the individual pixels.
Raster files display a wider array of colours, permit greater colour editing and show finer light and shading than vectors — but they lose image quality when resized. An easy way to tell if an image is raster or vector is to increase its size. If the image becomes blurred or pixelated, it’s most likely a raster file.
With vector image files, resolution is not an issue. You can resize, rescale and reshape vectors infinitely without losing any image quality. Vector files are popular for images that need to appear in a wide variety of sizes, like a logo that needs to fit on both a business card and a billboard.
Digital photographs are usually raster files. Many digital cameras automatically shoot and save photos as raster files — and the images you see online are often rasters, too. Raster files are also commonly used for editing images, photos and graphics.
Vector files work better for digital illustrations, complex graphics and logos. That’s because the resolution of vectors remains the same when resized, making them suitable for a wide variety of printed formats.
Some projects combine both raster and vector images. For example, a brochure may use vector graphics for the company logo but raster files for photography.
Raster files are generally larger than vector files. They can contain millions of pixels and incredibly high levels of detail. Their large size can affect device storage space and slow down page loading speeds on the web. However, you can compress raster files for storage and web optimisation to make sharing faster and easier.
Vector files are much more lightweight than raster files, containing only the mathematical formulas that determine the design.
You can open raster files in many different apps and web browsers, making them easy to view, edit and share. Vector files aren’t as accessible — many vector file types require specialised software to open and edit the files. Though it can present some challenges, it’s possible to convert vector files to raster or raster files to vector when needed.
Your software will usually determine your file type, whether it’s raster or vector. There are multiple types and extensions of both raster and vector files, each with its own features. Learn more about some of the common ones:
You can use Adobe Illustrator to convert a JPEG into a vector:
No, Adobe Photoshop is a raster-based programme, meaning it uses pixels to create detailed images. One of the primary uses of Photoshop is with digital photos, which are usually raster files. But, you can open and edit vector files in Photoshop — either as a smart object or rasterised file.
Adobe Illustrator is a vector-based programme. While Photoshop excels as a photo editor and graphic design programme, Illustrator specialises in creating scalable vector graphics, logos and design elements. You can open raster files in Illustrator and use the Image Trace tool to turn the image into a vector.
