UNIT 54 DIGITAL GRAPHICS

RASTER GRAPHICS Raster graphics are digital images created or captured (for

example, by scanning in a photo) as a set of samples of a given space. A raster file is usually larger than a vector graphics image file, A Raster file is full bit-map images. A raster file is usually difficult to modify without loss of information, although there are software tools that can convert a raster file into a vector file for refinement and changes. Examples of raster image file types are: BMP, TIFF, GIF, and JPEG files. An advantage of Raster Graphics is that the software for them is much cheaper than vector. The disadvantage is the Megapixels for the file, if you expand the image too much there wouldn’t be enough pixels to suit the image at the expanded size so the image starts to blur up. Raster graphics are used as web page backgrounds, solid objects like buttons or static title bars, and mpeg movies. Raster images are often created by saving a static snapshot of an image build up from overlaying many vector graphics. 

VECTOR GRAPHICS Vector-oriented images are more flexible than bit maps

because they can be resized and stretched. In addition, images stored as vectors look better on devices with higher resolution, whereas bit-mapped images always appear the same regardless of a device's resolution. Another advantage of vector graphics is that representations of images often require less memory than bit-mapped images do. Vector graphics is the use of geometrical primitives such as points, lines, curves, and shapes or polygon(s), which are all based on mathematical equations, to represent images in computer graphics, they are mainly used for either raster printing or shape printing, and very good for sign making as it uses mainly shapes, the main advantage is that data can be represented in original resolution without generalization and the main disadvantage is that vector images are not as cost effective as raster images

JPEG’S JPEG which stands for Joint Photographic Experts Group is a type of file

extension.  This is the right format for those photo images which must be very small files, for example, for web sites or for email. The file extensions for this format are .JPEG, .JFIF, .JPG, OR .JPE although .JPG is the most common on all platforms, A useful property of JPEG is that the degree of lossiness can be varied by adjusting compression parameters. This means that the image maker can trade off file size against output image quality. JPEG has a hard time with very sharp edges: a row of pure-black pixels adjacent to a row of pure-white pixels, for example. Sharp edges tend to come out blurred unless you use a very high quality setting. Edges this sharp are rare in scanned photographs, but are fairly common in GIF files: borders, overlaid text, etc. The blurriness is particularly objectionable with text that's only a few pixels high.

TAGGED IMAGE FILE FORMATTIFF or better know as Tagged Image File Formats a common format for exchanging raster graphics images between application programs including those used for scanner images. A tagged image file format can be identified with the file format .tiff or .tif,  The TIFF format was developed in 1986 by an industry committee chaired by the Aldus Corporation and is now used by adobe software. TIFF files are commonly used in desktop publishing, faxing, 3-D applications, and medical imaging applications. The main benefits of a .TIFF file format is that it can be compressed to reduce file sizes using mathematical algorithms such as ZIP or TAR without loss of image data but the downside of this is the large file sizes, around 20mb for a 10 megapixel image, so larger storages devices needed for long term archival use.

PSDPhotoshop files have default file extension as .PSD, which stands for "Photoshop Document. A PSD file stores an image with support for most imaging options available in Photoshop, PSD is a proprietary file that allows the user to work with the images’ individual layers even after the file has been saved.

Ideal for use when processing images as a user can save the file and then go back to it at a later date but the down side of a .PSD file is that it is generally only recognized by Photoshop software and certain other image manipulation software

METAFILE Microsoft uses this term for its Windows Metafile (WMF)

format. A WMF file contains a sequence of graphical-device-interface (GDI) function calls ("commands" to the OS) that results in the presentation of a graphic image. Using WMF files rather than already-built bitmaps saves space when many bitmaps are used repeatedly by different components of the operating system or of an application. In general, there are tools (such as HiJaak) that will convert the WMF, EMF, and CGM formats into other formats. EMF (Enhanced MetaFile) and raw are terms for spool file formats used in printing by the Windows operating system. You can think of the picture stored in an enhanced metafile as a "snapshot" of the video display taken at a particular moment. This "snapshot" maintains its dimensions no matter where it appears on a printer, a plotter, the desktop, or in the client area of any application. Drawing a metafile directly to a printer allows the printer to use it's high-quality resolution of 1200 DPI or so, while the screen usually only offers 96 DPI.

AI AI is a file extension for a vector graphics file format used

in an Adobe Illustrator drawing. Adobe Illustrator is a popular vector graphics-based drawing program.  The AI format is a strictly limited, highly simplified subset of EPS. AI stands for Adobe Illustrator. As an AI file is vector graphics based it means Vector-based formats mean artwork can be scaled up or down indefinitely without developing pixelated artifacts, as vector graphics is shapes and is all about precision, To create photo realistic drawing the user must have oodles of patience and a keen eye for detail and requires a lot of skill to master it.

3DS3DS is one of the file formats used by the Autodesk 3ds Max 3D modeling, animation and rendering software. 3DS files consist of blocks of data called "chunks" that contain an ID and length description. Chunks store the shapes, lighting, a viewing information that together represent the three-dimensional scene. As It is a 3d modeling software format, and there are many programs that do 3d modeling, you can use it with different programs such as Photoshop CC and Cinema 4D.

With the .3ds format, they don’t contain bones so you can only use them for unanimated props such as scenery or buildings. If you want to use boned animations for characters or NPCs you'll need to use .B3d files that support the bones.