Bit Depth

Bit depth is a computer graphics term which describes the number bits used to make up a single pixel in a bit-map

Pixels

Pixel is short for Picture Elements, pixels are small point of a graphic image. Graphic monitors display pictures by dividing into thousands or millions of pixels all aligned in rows and columns. They are so close together that it appears that they are joined together.

The number of bits used in a single pixel will vary depending on how many colours or shades of gray can be seen. For example, and 8-bit colour mode will use 8 bits for each pixel. 

On colour monitors, pixels consist of only three dots - a red, a green and a blue dot. The three dots should converge at the same point but some monitors have convergence errors which makes the colour pixels look fuzzy.

The quality of a display system depends mainly on the resolution, how many pixels it can display and how many bits are used to represent each pixel.

Raster Graphics

A Raster Graphic image is a group of rectangular grids called pixels which form together to make an image.

Here is an example of a Raster graphic Image.

 Raster Graphic Images are viewable via a computer monitor, paper, or other display medium. Raster images are commonly stored in image files with varying formats.

 Each pixel has an individually defined color; images in the RGB color space, for instance, often consist of colored pixels defined by three bytes — one byte each for red, green and blue. Less colorful images require less information per pixel; for example, an image with only black and white pixels requires only a single bit for each pixel. One can distinguish raster graphics from vector graphics in that vector graphics represent an image through the use of geometric objects such as curves and polygons.

Vector Graphics

Vector graphics is the use of geometrical primitives such as points, lines, curves, and polygons, which are all based upon mathematical equations to represent images in computer graphics.

Vector-Oriented images have alot more flexibility then bitmap images because they can be stretched and re-sized. Also the quality of a vector image is much higher that that of a Raster image and they also look better when stored on devices (monitors and printers) where as bitmap images look the same on any device. Another advantage of using a vector image is that the representation of an image often takes up less memory than a bit-map image.

 The majority of sophisticated graphics system use vector graphics because it shows a more detailed and better looking image that what a bit-map image would look like. In addition many printers also use vector graphics because they would print a higher quality image.

.JPEG

JPEG’s (Joint Photograhic Expert Group) compress large files into smaller files and are used very often on website, mostly they are used for image compression. Here is and example of a JPEG image:

JPEG images can vary from high quality to low quality depending on what settings have been chosen.