2. BTec Level 3
Extended Diploma in Creative Media Production
HA1 - Technical File – Raster and Vector Images
There are two kinds of computer graphics: Raster Graphics, these graphics are
made of pixels, and Vector Graphics that are made of paths. Raster images are
often referred to as bitmap images.
A bitmap or raster image uses lots 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
http://en.wikipedia.org/wiki/Raster_graphics
3. HA1 - Technical File – Antialiasing
• Antialiasing is a technique sometimes referred to as Oversampling. It is used in
computer graphics for smoothing out jagged lines that occur due to the output
device not having enough resolution to create a smooth line.
• Antialiasing works by surrounding the jagged lines with intermediate shades of
colour similar to the colour of the line This works to blend the colour into looking
more like a straight line than a jagged shape.
• The only downfall with Antialiasing Is that although it reduces the jagged effect of
the lines it also makes them appear fuzzier.
4. HA1 - Technical File – Resolution
• In computer graphics the resolution of something is the number of pixels in each
dimension that can be shown.
• Resolution is usually measured as Width x Height with the units in pixels, for
example 1024 × 768 meaning the width is 1024 pixels and the height is 768 pixels.
• The with and hight differences create different aspects like widescreen for
example.
• As far as the Image quality is concerned
higher numbers of pixels are better
this creates a better quality image
on the screen.
5. HA1 - Technical File – Aspect Ratio
• The aspect ratio of an image describes the difference between the width and the
height.
• This can often be written as two numbers separated by a colon for example 16:9
this can relate to images of any size for example 16 cm wide and 9 cm high or even
16 yards wide and 9 yards high.
• 4:3 is the standard for computers and old televisions whereas 16:9 is widescreen
and the usual HD format.
6. HA1 - Technical File – File Formats
• A GIF or Graphics Interchange Format is a bitmap image format that also supports
animations. A GIF only has 256 distinct colours for each frame making it unsuitable
to replicate real colour photographs but for images like Logos a GIF is perfect.
• A JPEG is a very commonly used method of compression for digital photography.
The amount of compression can be altered in order to differ between storage size
and image quality
• A TIFF or a Tagged image file format is a file format for storing images that is
popular for graphic artists, publishers and photographers.
• An EPS or an Encapsulated PostScript is a DSC confirming Post script document
which is intended to be usable as a graphics file format and has restricted content.
• A PSD stands for a Photoshop document. Basically a PSD file stores an image with
support for most of the imaging options available in Photoshop
• PDF stands for Portable Document Format. A PDF file is used to show documents
without operating software. Each PDF file creates a complete description of the
document including text, fonts, graphics and anything needed to display it.
7. HA1 - Technical File – Colour Models
• RGB is a colour model used in digital graphics that basically involves red green and
blue light being added together in various combinations to create a wide variety
of colours. The name RGB comes from the three primary colours red, green and
blue. Typical things that use RGB include Televisions such as LCD and Plasma,
computer and mobile phone displays.
• CMYK is another colour model used in digital graphics. CMYK comes from the four
colours used, Cyan, Magenta, Yellow and Key(Black). The CMYK model works by
partially or completely masking colours on a lighter, usually white, background.
The ink reduces the light that would otherwise be reflected.
