Task 2- Image file types
1. Properties of image file types:- Pixel dimesnion- are the number of pixels wide and the number of pixels tall of a sensor. They are multiplied to find the total number of pixels on a sensor.
- Dpi resolution (Dots per inch)- is a measure of printing or video dot density, in particular; the number of individual dots that can be placed in a line within the size of 1 inch (2.54 cm).
- Quality (of an image)- is a term which often is used to describe the amount of visibility of applicable information in an image. but when we judge an image quality on a camera or monitor, we may look at the sharpness or resolution, good contrast, correctness of colour, stages from black to white what is sometimes called "long scale".
- Compression settings- Compression, or "data compression," is used to reduce the size of one or more files. When a file is compressed, it takes up less disk space than an uncompressed version and can be transferred to other systems more quickly. Therefore, compression is often used to save disk space and reduce the time needed to transfer files over the Internet.
2. What do they mean:
- Bitmap/Raster- are made up of pixels of different colours. Bitmap graphics composed of many tiny parts, called pixels, which are often many different colours. It is possible to edit each individual pixel.
- Vector- are created in graphics packages and consist of shapes such as objects. Vector graphics are scalable - for example; when you resize them, they do not lose quality.
Bitmap (or raster) images are stored as a series of pixels. Each pixel is a very small square that is assigned a color, and is arranged in a pattern to form the image. When you zoom in on a bitmap image, you can see the individual pixels that make up that image. Bitmap graphics can be edited by erasing or changing the color of individual pixels using a program such as Adobe Photoshop. However, unlike bitmaps, vector images are not based on pixel patterns, but instead use mathematical formulas to draw lines and curves that can be combined to create an image from geometric objects such as circles and polygons. Vector images are edited by controlling the lines and curves that make up the image using a program such as Adobe Illustrator.Vector images tend to be smaller than bitmap images. This is because, a bitmap image has to sotre colour information for each pixels. But a vector image just has to store the mathematical formulas that makes up the image, which may take less space. Bitmap formats are best for images that need to have a wide range of color gradations, such as most photographs. Vector formats, on the other hand, are better for images that consist of a few areas of solid color. Examples of images that are well suited for the vector format include logos and type.
3. Different file types:
.tiff- A TIFF file, or TIF file, stands for Tagged Image File Format. TIF files are a common file format for images, especially those used on graphic design. The file extension for a TIFF file is either .tiff or .tif. TIFF files can be saved without compression, or they can be compressed to lower file size, similar to JPG files. TIFF files are commonly used in print design and desktop publishing because they can store large, high quality images such as photos. Often, printers will prefer or require TIFF files over JPG images or other formats. Since compression is not used by default on TIFF files, the file size is generally quite big. This is a big disadvantage of TIFF files. Uncompressed TIFF images can take up a lot more space than a JPEG. This means that digital cameras will not be able to save as many photos in the native TIFF format. It also causes a problem for when sending TIFF's via e-mail, in a lot of cases the attachment size is too big.
.jpg- JPG files, also known as JPEG files, are a common file format for digital photos and other digital graphics. When JPG files are saved, they use "lossy" compression, meaning image quality is lost as file size decreases. JPEG stands for Joint Photographic Experts Group, the committee that created the file type. JPG files have the file extension .jpg or .jpeg. They are the most common file type for images taken with digital cameras, and is widely used for photos and other graphics used on websites. Unlike GIF files, which show significant can lose photo image quality, JPGs allow for some degree of file size reduction without losing too much image quality. However, as the file sizes get very low, JPG images will become "muddy." When saving photos and other images as JPG files for the web, email and other uses, you must decide on this tradeoff between the quality and file size.
.png- Short for Portable Network Graphics, and pronounced ping, a new bit-mapped graphics format similar to GIF. In fact, PNG was approved as a standard by the World Wide Web consortium to replace GIF because GIF uses a patented data compression algorithm called LZW. In contrast, PNG is completely patent- and license-free. The most recent versions of Netscape Navigator and Microsoft Internet Explorer now support PNG. But however,PNG images also do not support animation. PNG can be made into multi-image files through the MNGextension of the format, but browser support is patchy for this format. Therefore, the web designer has to stick with GIFs for creating animations.
.bmp- Short for "Bitmap." It can be pronounced as "bump," "B-M-P," or simply a "bitmap image." The BMP format is a commonly used raster graphic format for saving image files. It was introduced on the Windows platform, but is now recognized by many programs on both Macs and PCs. The BMP format stores color data for each pixel in the image without any compression. For example, a 10x10 pixel BMP image will include color data for 100 pixels. This method of storing image information allows for crisp, high-quality graphics, but also produces large file sizes. The JPEG and GIF formats are also bitmaps, but use image compression algorithms that can significantly decrease their file size. For this reason, JPEG and GIF images are used on the Web, while BMP images are often used for printable images.
.gif- GIF stands for "Graphics Interchange Format," GIFs can contain a maximum of 256 colors, and are therefore best for images that contain simple shapes, a limited color palette, text and other elements as opposed to photos. GIF images use a compression formula originally developed by CompuServe (which is seen as "CompuServe GIF" in Photoshop). GIF files have the file extension .gif. GIF files are compressed using "lossless" compression, meaning image quality is not sacrificed as file size may reduce. However, if you save images with many colors as GIF files with a limited color palette, you will notice a reduction in quality. Unlike JPG files, GIF files support transparent backgrounds. This allows GIF files to blend with website background colors. But, since pixels can only be 100% transparent or 100% opaque, you cannot use them for partial transparency, drop shadows, and similar effects. To achieve that problem, PNG files are best. GIF files can also contain animation, creating files known as animated GIFs. These are commonly seen on websites, though they are not as widely used as they used to be
.pdf- PDF stands for "Portable Document Format." PDF is a multi-platform file format developed by Adobe Systems. A PDF file captures document text, fonts, images, and even formatting of documents from a variety of applications. You can e-mail a PDF document to your friend and it will look the same way on his/her screen as it looks on yours, even if she/he has a Mac and you have a PC. Since PDFs contain color-accurate information, they should also print the same way they look on your screen. PDF files are especially useful for documents such as magazine articles, product brochures, or flyers in which you want to preserve the original graphic appearance online. A PDF file contains one or more page images, each of which you can zoom in on or out from. You can page forward and backward.
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