At some point, all of us have laughed at a hilarious animated GIF or shared a beautiful JPEG photo. These are just a couple of examples of raster file types. Everyone who uses a laptop, tablet, cellphone or digital camera will come into contact with raster graphics on a daily basis—but how much do you really know about them? This article and infographic will give you a handy rundown of some of the most common raster file types, their pros and cons, and their specific uses.
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Common features of raster images
Whilst all raster image formats are different, there are a few basic features which all of them share.
Raster graphics are one of the two most common methods used to display images, and can be contrasted with vector graphics. When you take a photo with a digital camera, scan an image using your scanner, or view most computer graphics, then you’re dealing with raster graphics. Paper patterns used by many industries as prototypes are mostly in raster format as well.
A raster image is essentially a rectangular grid. Within this grid lie thousands of tiny individual squares of color, known as pixels. Together, these pixels form the image that you see on screen. However, each pixel acts independently from all the pixels around it. So, when you zoom into a raster image, you’re not making the image bigger—you’re actually making each individual pixel within the image bigger. As a result, zooming into or scaling a raster image can leave it looking blurry and undefined. Raster images are only intended to be viewed at a particular size, and lose quality when scaled up or down. This is known as resolution dependency.
Overall evaluation of raster images
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Raster File Types
JPEG/JPG
The JPEG format is named for the organization which created it, the Joint Photographics Expert Group. This is an extremely common format, and is typically used for sharing photographs. Its small size means that digital cameras are able to store large numbers of photos with a small amount of memory.
Our ultimate guides will teach you everything you need to know about JPEG to DWG conversion—or, click here to find out how to convert from JPEG to DXF.
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JPEG 2000
JPEG 2000 was created to improve upon the existing JPEG format. Whilst the original JPEG format caused images to lose quality when compressed, JPEG 2000 was designed to combat some of this loss in quality. It uses a wavelet-based method to compress images, with the goal of storing higher quality images within a small file size. Despite these advances, JPEG 2000 has not become a widely-used format.
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GIF
One of the most common image formats on the web, GIFs (Graphics Interface Format) are typically used for web graphics. Unlike many other formats, GIF also supports animated images. The popularity of animated GIFs is such that GIF has become one of the most widely-recognized file formats around—and for many people, “GIF” is synonymous with “animated GIF”. To learn about GIF to DXF conversion, click here.
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PNG
PNG is the most used lossless image format on the internet. The format was created to improve upon the existing GIF format. There were clear deficiencies with GIF, but as it was patented, there was no way for external programmers to improve upon it. The idea thus came about for a replacement format: PING, to stand for PNG Is Not GIF. At the time, only 3-letter file extensions were available, so PING became PNG. Nowadays, PNG officially stands for Portable Network Graphics.
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BMP
Bitmap is one of the simplest file formats in raster graphics. Whilst other raster formats are more complex, a bitmap (or BMP) file simply contains information about each individual pixel in the file. In the past, BMP files were uncompressed, leading to huge file sizes. Now, it’s possible to compress BMP files using lossless compression, though uncompressed bitmaps are still available.
Because of its simplicity, virtually every device imaginable supports BMP files. However, its huge file size means that in most circumstances, BMP is one to avoid. If, however, you still need to convert using this file format, find out more about how to use Scan2CAD to convert BMP to DXF.
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TIFF
TIFF (or TIF) is a commonly-used file format in the fields of printing, graphic design, and photography. TIFF stands for Tagged Image File Format, as TIFF files also include tags containing additional information about the image. It uses lossless compression, and is useful for storing high-quality images.
Due to its high quality, it is a good file format to choose if you want to vectorize your raster image. In fact, Scan2CAD recommends saving your image files as TIFF before converting to DWG or DXF in order to increase your chances of optimal vectorization results.
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PCX
One of the first widely accepted image formats, PCX (Picture Exchange) was created in 1985 to serve as the native file format of the PC Paintbrush software. In the proceeding decades, however, newer formats (such as JPEG, PNG, and GIF) have superseded PCX, and it is no longer a common format.
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Which raster file type should I use?
If you’re here on the Scan2CAD blog, though, you’re probably interested in knowing which format is the best to choose for converting from raster to vector. We recommend saving your raster images in TIFF format due to their lossless compression and support for high-quality, true color images. Their file size may be a concern for certain applications, but for vectorization purposes, the good image quality offered by TIFF is crucial.
Whilst this list covers some of the most commonly-used raster formats, it is not exhaustive. There are hundreds of different file types available—check out which raster (and vector) file types are supported by Scan2CAD.
Interested in converting from raster to vector? Try out Scan2CAD’s free 14-day trial today and make the most of its vectorization tools, OCR capabilities, and editing suite.
