For anyone who is new to the study of design, the difference between raster and vector graphics can at first seem complex. After all, both electronic files are made up in different ways to represent images. Both types also have their own applications, as well as their advantages and disadvantages.
In this article, we will banish all the confusion and explain the major raster and vector differences in a way that’s easy to understand. Read on so you’ll always choose the right format for your digital printing job.
What are Raster and Vector Images?
Before we actually delve into the differences between raster and vector graphics, let’s first understand what they are individually. Two basic terms to take note of as we go along:
Pixel – in computer graphics, a pixel is a dot or the smallest addressable element of an image represented on a screen. Most photos we see on a computer screen are raster images as they are made up of hundreds of pixels. An image made up of a collection of pixels is known as a bitmap.
Bitmap – a bitmap is a digital image composed of a matrix of dots or pixels. When viewed at 100%, each dot corresponds to an individual pixel.
What is a raster image?
Raster images, also known as bitmap images, are made up of a bunch of tiny pixels. They’re like a mosaic made up of tiny pixels and each pixel is a tiny square with a specific color. When viewed from a distance, these pixels mix or blend together to form a clear image. Raster graphics have no limit to how complex or detailed they can be, but as you start to scale the image beyond its original size, you will notice a drop in quality.
This is because the number of pixels in which the image is divided determines its sharpness and detail. The more pixels, the higher the quality. However, a higher resolution results in a larger file size.
Most images you find on the web are raster graphics with file extensions such as JPG, PNG, BMP, PSD, or GIF. Photographs are the most common type of raster image. The most popular tool for creating and editing raster images is Adobe Photoshop. This is because Illustrator is better for drawing illustration, complex shapes, and creating the layout of single-page documents.
What is a vector image?
The major difference between raster and vector images is that vector graphics are not made up of pixels. They are made of paths, each with a vector or mathematical equation that controls the shapes and colors. The graphics are defined on a plan, connected by lines and curves. This means that they are relatively simple and are somewhat limited in the number of details and effects you can include.
However, the most significant raster and vector difference lies in the quality of the output. Vector images can be enlarged infinitely, and they will never lose their quality.
The most common types of vector images are logos and text. Say, for instance, you’re learning how to print stickers for your brand’s logo, it’s best to use vector images for your print job.
The most common file extensions for vector graphics are PDF, EPS, AI, and SVG. A difference between raster and vector graphics is also the most popular tool that designers use. While raster graphics are using Adobe Photoshop, vector graphics are made with Adobe Illustrator. This is because Photoshop is best at manipulating images and creating graphics for banners and websites. Its text tools are also great for low-resolution elements like website headers and buttons.
Another major difference between raster and vector images is that designing vector graphics requires a bit more technical expertise and practice. If vector graphics are used in interactive animations, specialized knowledge and experience are recommended with different optimization techniques.
When to Use Vector vs Raster Graphics
Now that you know the difference between raster and vector graphics, it’s time to discuss when to use vector vs. raster. Since vector graphics are infinitely scalable and have significantly smaller sizes, they seem to be the ideal format. However, both raster and vector have their individual pros and cons. Each format also works better or worse for certain applications.
When to Use Raster Images
Raster images are the preferred format when working with photographs. Photos taken with a digital camera or copied on a scanner result in raster images.
Almost all of the images you find on websites are raster graphics, even those originally created with paths. Raster images are typically used for digital publication and for printing photographs in printed mediums like newspapers, books, and magazines. So that the quality will not suffer during the printing process, images are saved at a high DPI (dots per inch).
When to Use Vector Images
Vector images are the number one option when designing or creating an illustration or logo. Due to the way the graphics are created and saved, you have more flexibility with making edits and using your image in a variety of sizes. Type and fonts are also created as vector images, which allows you to change their size without compromising quality. This helps certain typefaces maintain their smooth shapes and edging while keeping the type from looking blocky.
Most companies create their logos and insignia in vector file formats. The files are then saved and used as the basis for rasterized copies to be used in web and print publishing.
Can I Use Both Raster and Vector Images?
Of course, just because there are many differences between raster and vector doesn’t mean they can’t be used in a single output. Many projects actually combine raster and vector images together. For instance, a brochure might include a corporate logo (vector) and a photo of the products or services (raster).
Other examples include personalized calling cards that combine corporate logos and text (vector) with photos (raster), an online catalog with product images (raster) alongside scalable product information tables (vector), or printed postcards that feature a foreground photo (raster) and an illustrated background (vector). You can use both Illustrator and Photoshop to pair both raster and vector graphics.
Raster Graphics vs Vector Graphics: Major Pros and Cons
We have discussed what raster and vector images are and when to use them. To clearly delineate their individual applications, here is a breakdown/refresher of the major differences between raster and vector graphics.
Raster Graphics Strengths
- As a general rule, raster files handle the subtleties of photographs in an excellent manner.
- Raster can better handle additional effects such as texture, shading, and blurring.
Raster Graphics Limitations
- Raster file formats are highly dependent on image resolution to accurately reproduce the quality in print. Due to pixelation, it is often a bad idea to enlarge raster images.
- Raster files can take a huge amount of memory if there is a large number of pixels and details in an image. This makes storing and sharing the files more difficult.
- It’s difficult to convert raster images into vector files.
When to Use Raster Graphics
- Always use raster images in designs that require photography.
- Raster files are ideal for website design.
- Use raster graphics when you want to add effects to images such as textures, gradients, blurs, or other types of image manipulation.
Vector Graphic Strengths
- Vector graphic file sizes are easier to store and share as they are much smaller compared to raster graphics.
- If needed, converting a file from vector to raster is quick and easy.
- Vector images are not dependent on resolution. You can make them smaller or larger without sacrificing image quality.
Vector Graphic Limitations
- Vector files are not suitable for handling photographic imagery.
- They have to be converted into pixels each time they will be displayed on a screen.
- Vector images are not good at displaying filters and color gradients.
When to use Vector Graphics
- When you are designing or creating large-scale graphics such as banners, vehicle wraps, signage, and other large-format items.
- Vector graphics are the best choice for logos, promotional posters, major illustrations, and other types of business identity print work.
To end the raster graphics vs. vector graphics debate — ultimately, it all boils down to what you’re creating and your intended use for your images. If you need a brand logo that will be used over and over again in multiple media (digital, print, signage, etc.), create a vector image that can be scaled. If you want to edit a photo, create a raster that is capable of mimicking the natural qualities of light and render complex color blends.
Of course, the differences between raster and vector discussed in this article just scratch the surface but hopefully, you have a better understanding of their main features and applications. For more comparison articles like this one, check out our comprehensive post on digital printing vs. offset printing.