Centre for Distance Learning and Innovation

Outcomes

In this lesson you will

describe how bitmaps are constructed
explain the limitations of bitmap images
explain the need for image compression
distinguish between lossy and lossless compression
determine the effect of different amounts of compression on image quality and file size

Students will:

demonstrate knowledge of the impact of graphics communications systems
employ the elements and principles of visual design in creating images, and to construct print and web layouts
use a variety of imaging, storage, and transmission tools
analyze visual messages to determine the appropriateness of their design elements to the effectiveness of the message

This section

introduces the two basic types of computer images
- bitmaps as collections of dots, each of which can have a different colour
- vector images as collections of objects, defined by mathematical formulae, each of which can have different features such as colour, fill, transparency and so on.
introduces traditional methods for creating and reproducing images
- screen printing (serigraphy) as forcing ink through a mesh that has areas blocked out where ink will not go through
- relief printing as blocks with ink on raised areas so that the pattern can be transferred to a surface
- gravure or intaglio as cut lines or etched lines in a flat surface into which ink is wiped for transfer to paper or other medium
- lithography as grease based patterns of a surface, to which ink adheres for transfer to paper or other medium
introduces computer-based methods of reproducing images
- dot matrix as a row of pins striking an ink ribbon placed over the paper
- inkjets as devices which spray very tiny droplets of ink onto the paper or other surface
- lasers as devices which draw the image onto electrostatically charged drums for transfer to paper, where it is heated and fused to the paper

To be successful in this lesson, it would be helpful to know the following: