2. Raster and Vector Images
• There are two kinds of computer graphics - raster (composed of pixels) and vector (composed of paths). Raster images are more
commonly called bitmap images.
A bitmap image uses a grid of individual pixels where each pixel can be a different colour or shade. Bitmaps are composed of pixels.
Vector graphics use mathematical relationships between points and the paths connecting them to describe an image. Vector graphics
are composed of paths.
The image to the left below is representative of a bitmap and the image to the right is representative of a vector graphic. They are
shown at four times actual size to exaggerate the fact that the edges of a bitmap become jagged as it is scaled up:
• I created this document with information used from the following website: http://www.sketchpad.net/basics1.htm
• Vector Image Raster Image
• I found these images at http://www.sketchpad.net/basics1.htm and http://logodesignpro.com/index.php?staticpage=vector_raster
3. Antialiasing
• In computer graphics, anti aliasing improves the
appearance of polygon edges, so they are not
"jagged", but smoothed out on the screen.
However, it incurs a performance cost for the
graphics card and uses more video memory. The
level of anti-aliasing determines how smooth
polygon edges are (and how much video memory
it consumes).
• I found this at
http://en.wikipedia.org/wiki/Spatial_anti-aliasing
4. Resolution
• Image resolution is an umbrella term that describes the detail an image
holds. The term applies to raster digital images, film images, and other
types of images. Higher resolution means more image detail.
• Image resolution can be measured in various ways. Basically, resolution
quantifies how close lines can be to each other and still be visibly resolved.
Resolution units can be tied to physical sizes (e.g. lines per mm, lines per
inch), to the overall size of a picture (lines per picture height, also known
simply as lines, TV lines, or TVL), or to angular subtenant. Line pairs are
often used instead of lines; a line pair comprises a dark line and an
adjacent light line. A line is either a dark line or a light line. A resolution of
10 lines per millimetre means 5 dark lines alternating with 5 light lines, or
5 line pairs per millimetre (5 LP/mm). Photographic lens and film
resolution are most often quoted in line pairs per millimetre.
• I found this information at http://en.wikipedia.org/wiki/Image_resolution
5. Aspect Ratio
• The aspect ratio is an image projection attribute that describes the
proportional relationship between the width of an image and its
height.
• It is expressed as two numbers separated by a colon. That is, for an
x:y aspect ratio, no matter how big or small the image is, if the
width is divided into x units of equal length and the height is
measured using this same length unit, the height will be measured
to be y units. For example, consider a group of images, all with an
aspect ratio of 16:9. One image is 16 inches wide and 9 inches high.
Another image is 16 centimetres wide and 9 centimetres high. A
third is 8 yards wide and 4.5 yards high.
• I found this information at
http://en.wikipedia.org/wiki/Aspect_ratio_(image)
6. File Formats
• GIF – CompuServe's Graphics Interchange Format
• JPEG, JFIF (.jpg or .jpeg) – Joint Photographic Experts Group – a lossy image format
widely used to display photographic images.
• EPS – Encapsulated Postscript
• TIFF (originally standing for Tagged Image File Format) is a file format for storing
images, popular among graphic artists, the publishing industry, and both amateur
and professional photographers in general
• PSD (Photoshop document), the default file extension of the proprietary file
format of Adobe System's Photoshop program.
• Portable Document Format (PDF) is an open standard for document exchange. This file
format, created by Adobe Systems in 1993, is used for representing documents in a manner
independent of application software, hardware, and operating systems
• I found this at http://en.wikipedia.org/wiki/Tagged_Image_File_Format, http://en.wikipedia.org/wiki/PSD,
http://en.wikipedia.org/wiki/List_of_file_formats
7. Colour Model
• A colour model is an abstract mathematical model
describing the way colours can be represented as
tuples of numbers, typically as three or four values or
colour components. When this model is associated
with a precise description of how the components
are to be interpreted (viewing conditions, etc.), the
resulting set of colours is called colour space. This
section describes ways in which human colour vision
can be modelled.
• I found this information at
http://en.wikipedia.org/wiki/Color_model
8. Adobe Photoshop
• Adobe Photoshop is a graphics editing program developed and
published by Adobe Systems Incorporated.
• Adobe's 2003 "Creative Suite" rebranding led to Adobe Photoshop
8's renaming to Adobe Photoshop CS. Thus, Adobe Photoshop CS5
is the 12th major release of Adobe Photoshop. The CS rebranding
also resulted in Adobe offering numerous software packages
containing multiple Adobe programs for a reduced price. Adobe
Photoshop is released in two editions: Adobe Photoshop, and
Adobe Photoshop Extended, with the Extended having extra 3D
image creation, motion graphics editing, and advanced image
analysis features
• I found this at http://en.wikipedia.org/wiki/Adobe_Photoshop
9. Adobe Illustrator
• Adobe Illustrator is a vector graphics editor
developed and marketed by Adobe Systems.
Illustrator is similar in scope, intended market,
and functionality to its competitors, CorelDraw,
Xara Designer Pro and Macromedia FreeHand.
The latest version, Illustrator CS5, is the fifteenth
generation in the product line.
• I found this at
http://en.wikipedia.org/wiki/Adobe_Illustrator
10. Adobe InDesign
• Adobe InDesign is a software application produced by Adobe
Systems. It can be used to create works such as posters, flyers,
brochures, magazines, newspapers and books. InDesign can
also publish content suitable for tablet devices in conjunction
with Adobe Digital Publishing Suite. Graphic designers and
production artists are the principal users, creating and laying
out periodical publications, posters, and print media. It also
supports export to EPUB and SWF formats to create digital
publications, and content suitable for consumption on tablet
computer devices. The Adobe InCopy word processor uses the
same formatting engine as InDesign.
• I found this at http://en.wikipedia.org/wiki/Adobe_InDesign
