Bitmap image definition - A set of bits that represents a graphic image, with each bit or group of bits corresponding to a pixel in the image.
The American Heritage® Dictionary of the English Language, Fourth Edition copyright ©2000
Vector image definition - a computer image that is stored in memory as lines rather than a series of dots, allowing it to be rotated or proportionally scaled. Based on the Random House Dictionary, © Random House, Inc. 2011.
Images made up on the computer and put onto the computer can be made in two different ways. Vector and bitmap images have both similarities and differences but both are good ways of creating images and have many uses. For example you may be sending images round the web or putting them up on websites, or maybe even just using them for print. Each type presents different ways of editing the image on programs such as Adobe Photoshop and Adobe Illustrator to create a desired effect or finish.
An overview - Bitmap and vector images in basic terms are different because bitmap images are made up of many small individually coloured squares called pixels, and vector images are simply coloured shapes put together to create the image. A photograph would be a bitmap image on the computer because of how many colours there are, (you could make this image using a vector program but you would need to use many tiny shapes anyway!) as opposed to a large banner logo which would probably be made on a vector program as it can be scaled without an issue.
Putting the bits together… Bitmap images on screen are displayed at 72 dots per inch and print at 300 dots per inch. Formats for bitmap images include JPEG, PNG, GIF, BmP, Tif and Psd. But less of the tech – spec, what are bitmap images actually good for? Well, they are very useful for complex and detailed images including photographs (Previously covered.) so this can cover a wide variety of media including images for the web, articles and image orientated sites or magazines. Uncompressed bitmap images will be very large in file size compared to an compressed bitmap file or a vector image file. Also, because bitmap images are made up of individual pixels and are so complex, you cannot enlarge the image as this will degrade the quality of the image and make it become pixilated. (Or interpolation.) This means that the image may become blurry or it’s even possible to see the individual pixels of the image. Look at the animation; see how the image becomes pixilated as it zooms in. You may have already experienced this by getting an image off of the web and then trying to enlarge it on a program, such as Microsoft Word.
With bitmap image creating programs such as Adobe Photoshop users are also able to create many effects and designs to create the desired outcome. By using layers, different images can be put on top of one another and altered in ways by changing their transparencies, transforming the image (sizing It.) and many other tools in between to make stunning images. Here is an example of a bitmap image, one being partially transparent, (opacity at 50%) the other being the original.Now on to vector images. As previously covered, vector images are made up of not many individual pixels but of lines, curves and shapes. Areas in industry that would need to use these images would be professions like graphic designers for a company logo, where the image would need to be enlarged for large scale items such as a shop banners, maps and diagrams or scaled down for items such as individual products, or for their logo on work papers. This is a great advantage over bitmap images because the image can be easily transformed without having to worry about the item becoming pixilated or distorted. In the editing process there are many tools in programs such as Adobe Illustrator including, draw, shape, transform, transparency tools as well as many, many others to create the desired image. An upside to editing vector images is that if you wish to erase a certain shape, it can be easily deleted whereas in a bitmap image the eraser tool would simply just delete pixels relative to where you use the tool. Also, for many tasks, vector images need to be converted to bitmap images, either for web displays of other functions. (Vector images can always be converted to bitmaps; this does not work vice versa.) This means editors can have the image at the size of their choosing before converting the image to bitmap so they can still have high quality images that are large. Although larger images will take up much more memory space, in general terms vector images will have smaller file sizes. Formats include ai, eps, 3ds, Swf, Sug.
In summary the two types of computer created imagery are obviously different because they are used for different jobs. You wouldn’t scale a small bitmap image to be large, and you wouldn’t create a vector image to replicate a very complicated photograph colour - wise. The actual quality of an image depends on the quality of your computer screen but pixilated images can still easily be seen usually. When images are scaled down for example a web page, the computer has to throw away pixels. When a vector image is resized or scaled down for example for print, it simply just becomes smaller, the scale is lower. In a lot of ways vector and bitmap images will combine, usually a vector image being transformed into a bitmap image for a different program. Because they are different and are edited differently, there are usually jobs for creating them in the interactive media industry will hold different titles and need different training. Also they may lead on to different areas of the industry. Bitmap image designers could move on to other media such as creating images for a computer game whereas vector image designers could move on to design items such as logos for companies. Obviously the paths of the two are not set as they can combine easily but the two types of imagery have their differences for different objectives.
1048 words.
Alex Mold.
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