DIGITAL IMAGING

Digital images

Digital images can be broken into two categories, artificial or natural.

A natural image is something like a photograph or a scanned picture. This is where the image is digitalized by the computer to read then stored or manipulated.

Artificial images or graphics are images that have been on the computer using software or other computer processors.

Vector images

Vector images are created on the computer to by using mathematic algorithms to create basic shapes, lines and arcs and such. These shapes are used to make shapes. These can be manipulated, resized or warped without loss of resolution or quality.

Raster imager

Rasters, also called bitmap, are images made on a computer using pixels. Pixels are arranged in grids where they combine colours and tones to produce a picture or graphic. Raster imaging is best suited for complex or photos. The main issue that is presented by raster images is that they are highly dependant on their resolution, meaning that alteration is difficult without changing the resolution somehow.

Image file format

All files on a computer takes a certain form of a specific format. These different formats allow the computer to determine what the file contains, i.e. picture, word doc., shortcut, etc. When the file is saved it automatically adds a four letter code that identifies what format that the file has been saved as.

.Jpeg

.Jpeg stands for Join Photographic Expert Group and is the most common file format for pictures and images. This format is best suited for images that have shading or any slight changes in colour and lighting effects. This format unfortunately loses quality when altered.

.Gif

The term .Gif stands for Graphic Interchange Format. This format is cross platform and compressed. It’s limited to a colour depth of 8 bits (256 colours) and, unlike .jpeg, will allow some colours to be transparent. This format uses a Lossless compression scheme that allows it to be manipulated without affecting the quality, the lossless scheme .gif’s use is called LZW. This ‘no loss’ of quality allows good quality pictures to be compressed and shared on the internet without loss of quality.

.TIF

.TIF is a common format used when images and graphics need to be used by devices other than the computer. This allows images to be accessed through things like printing devices without the control of a computer, it is commonly used for printing things such as logo’s. This format uses the same compression scheme as .gifs, it has very high resolution but is not ideal for sharing on the internet.