What is Raster Graphics? Definition, Uses & File Formats
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If you have been conversant with computer graphics terms, then there must have been times when you heard the words “raster” and “vector.” Though you may not understand what both terms mean or even the difference between them, one can already tell these two are inevitable when it comes to developing designs.
Digital photos and detailed graphics both come in raster form. The most popular types of raster files include JPEGs, PNGs, and GIFs Images while vector graphics include SVGs, EPSs, and PDFs.
If you are looking to understand raster graphics better, understand what they are, where to use them and other important information about them, keep reading this value-packed information to learn more about raster graphics.
What are Raster Graphics?
Raster graphics, otherwise called bitmap graphics are digital images that comprise tiny rectangular pixels or picture elements that are arranged in a grid or raster of x and y coordinates in a way that forms an image. The way it also has information mapped directly to the display’s grid explains why it’s called a bitmap.
Raster graphics store image data as fixed pixels. These pixels, mostly represented by a single color are fitted onto a grid. The file size of a raster image depends on the size of the image, which is determined by the number of pixels used in the image.
High-resolution images use smaller pixels and tend to have more pixel density – a value known as either DPI (Dots Per Inch) or PPI (Pixels Per Inch). Essentially, this means that an image with 1280×720 resolution will contain 921,600 pixels while a full HD image with a 1920×1080 resolution will have 2,073,600 pixels.
Similarly, high-definition photos usually have 300 DPI or more, while standard-definition photos are around 72 DPI.
Raster Graphics Vs. Vector Graphics: What’s the Difference?
Vector graphics use mathematical equations, lines, and curves with fixed points on a grid to produce an image. Unlike raster graphics, there are no pixels in a vector file instead it uses mathematical formulas to capture shape, border, and fill color to build an image.
Raster graphics on the other hand are images built from pixels (tiny color squares that can form highly detailed images in great quantity such as photographs). The more pixels an image has, the higher quality it will be, and vice versa.
Raster graphics and vector graphics are the two most popular formats used for visual content. These two formats are used to represent images in different ways, some of which include the following:
One of the key differences between raster graphics and vector graphic is their image resolution. Although raster graphics show a wider array of colors, enable more color editing, and show finer light and shading than vector, it loses image quality when resized. Whereas, vectors can be resized, rescaled, and reshaped without losing any image quality.
Rasters are usually digital photographs and this is mainly because most digital cameras automatically save photos as raster files -JPEGs and PNGs. Similarly, the images you see online are also rasters and are commonly used for editing images, photos, and graphics.
Vectors graphics on the other hand are better used for digital illustrations, complex graphics, and logos, which is mainly because the image quality remains intact after resizing, reshaping, or rescaling it.
3. File Sizes
Raster images are usually larger and contain more pixels and higher levels of detail than vector files. Although this can significantly impact the device storage space and slow down the website loading speed, a raster file can be compressed to take lesser space and increase web loading speed. Vector images on the hand are more lightweight.
4. Compatibility and Conversion
A raster image file can be viewed on different apps and web browsers, which makes them easy to view, edit and share whereas vector files are not very accessible, because they mostly require specialized software to open and edit the files.
5. File and extension types
In most cases, the software you are working with will determine the file type, whether it’s raster or vector. However, raster and vector files have some of the common extensions.
Raster file types include Joint Photographic Experts Group (JPEG – .jpg), Portable Network Graphics (PNG – .png), Graphics Interchange Format (GIF – .gif), Bitmap Image File (BMP – .bmp), Tagged Image File Format (TIFF – .tiff) and Adobe Photoshop File (PSD – .psd)
Vector file types include Scalable Vector Graphics (SVG – .svg), Encapsulated PostScript Files (EPS – .eps), Adobe Illustrator Files (AI – .ai), Collaborative Design Activity (COLLADA – .dae), PostScript (PS – .ps), and Enhanced MetaFile (EMF – .emf)
Advantages and Disadvantages of Raster Files
Some of the advantages of raster images include:
- Widely compatible: As stated above, most raster files are accessible and can be opened by many different programs, apps, and web browsers which makes it easy to view, edit and share the images.
- Attention to detail: Raster images display more colors and contain more pixels, and higher levels of detail are found in high-resolution images when displayed in the right dimensions. Essentially, the more pixels a file contains, the stronger the image quality is. \
- Precise editing: Raster images allow you to edit or enhance the graphic or photograph to fit your specific design needs.
Some of the disadvantages of raster images include:
- Large file sizes: A raster file usually consists of millions of pixels which help create highly detailed images. The downside of this is that it makes the file size large taking up more device space and slowing down a website speed.
- Resolution dependent: Raster files have millions of pixels to create high-quality photographs. This makes them very dependent on resolution and changes in size can significantly affect the visual quality of the image, thereby reducing the number of ways you can use these images.
- Fabric printing issues: The square pixels on most raster images make it a bit challenging to transfer them well to fabrics and clothing. This explains why vector graphics are commonly used for creating t-shirts, logos, and prints compared to raster format.
Applications of Raster Graphics
Raster graphics are used in the following ways;
1. Image Storage
The majority of computer images are stored in a raster graphics format such as JPEGs, PNGs, and GIfs, which are the popular options for websites and apps.
2. Photo-related designs
Raster images are commonly used in designs that require images because it renders them more than vector images.
For instance, designs in the trail industry, FMCG, and other customer-facing segments often require high-quality photographs of people, places, and things to make them look good. and attractive. In such cases, you can use a raster image.
3. Web Design
Raster images are a better option and a common go-to choice for website designers because they have the ability to achieve deeper hues, give the design a more natural look, and better color transitions as long as the right resolution is used.
4. Large-scale editing
If you are looking to do a lot of editing or add effect to an image(s), then you are better off using raster images.
Considering that they are more susceptible to pixel-level editing, raster images enable photo editors to try out different editing and effect on the image such as the blurred background. aura-like glows, shadows and so much more.
Raster graphic files and extension types
The main raster file types and extensions include the following:
1. JPEG: Joint Photographic Experts Group (JPEGs) is the most common raster file type and image found on the web. The compression degree of a JPEG image can be adjusted and is easily editable, however, once you edit a high-quality Jpeg image, you cannot regain that quality gain by reversing it. The file extension is .jpg or .jpeg.
2. PNG: Portable Network Graphics is a raster image format that supports lossless data compression (images that don’t lose image quality after it’s been reduced) and also has background transparency. This makes it the best option for web professionals.
3. GIF: Graphics Interchange Format is a bitmap image format that has become so popular on the web because of its light animations and wide support and portability. Gifs support up to 8 bits per pixel for each image and animation and a separate palette of 256 colors for each frame. Gifs have now become a popular replacement for emojis on chat apps.
4. BMP: Bit Map Picture or Bit Map Image is a dot matrix data structure that is used to store bitmap digital images free from the barriers on the display device. BMPs are mostly used to store two-dimensional digital images and data of raw images. One of its advantages is that it keeps the image quality while still saving it in other raster formats.
5. TIFF: Tagged Image File Format is popular among graphic artists, photographers, and print media for storing graphics images. It is flexible, and adaptable and can store images without losing their quality. It is also mostly used for optical character recognition, desktop publishing, image manipulation, scanning, word processing, faxing, and page-layout applications
6. PSD: is a short form of Photoshop Document and is the primary image format that Adobe Photoshop creates. A PSD file’s maximum height and width is 30,000 px with a file size of 2 GB. It can be edited anytime using its individual layers and you have to save it as PSD before converting it to other image formats.
Raster Graphics are digital images such as JPEGs, PNGs, and GIFs that you can easily find online on the internet, on websites, and on apps. They differ from vector graphics in terms of size, resolution, compression, and applications.
While most raster images are high-quality photographs with details and colors, vector images are illustrations with lower file sizes and don’t lose quality when resized.
We have provided up-to-date information about raster graphics and how they differ from vector graphics in this blog, hopefully, it is explanatory enough to help you choose the best possible file types for your specific needs.