Each pixel set to a number of
bits, which can contain a set
number of colours
If the pixel contains 4 bits, it can contain
up to 2^^4 number of colours (16)
Increasing the size of the image increases the
size of the file as there are more pixels
Increasing the resolution
(quality) also increases
file size
The width of the
picture is needed in
pixels as well as
the number of bits
assigned to each
pixel
Vector
Images
These images do not have
any data pixels but they
are a specific set of
instructions needed to
reproduce the picture
Certain elements of the
picture are required to
make the instructions
Shape
Line
thickness
FIll
Colour Depth
Vector images build
their instructions in
relation to the photo's
point of origin
As the picture is only a set of
instructions, resizing the photo does
not affect the resolution of the
picture
Therefore file size is
small
Metadata
Known as "data about
data"
vector images need metadata
This includes
Colour depth in bits per pixel
Date of creation
Resolution (height and width in pixels)
The Author
Number systems
Binary
Base 2 counting system, where
only the numbers 0 or 1 are
used
Computers read
data in binary
Denary
Base 10 counting system
where the numbers 0 to 9
are used
Humans use denary to
count
Hexadecimal
Base 16 counting system where the numbers 0 to 9 are
used, and the letters A, B, C, D, E, F are used to represent the
numbers 10, 11, 12 ,13 ,14 15 respectively
Units of
Information
Bit
Nybble
Byte
Kilobyte
Megabyte
Gigabyte
Terabyte
Petabyte
Exabyte
Yottabyte
Zettabyte
Sound
Sound waves are analogue, so they
must be converted to digital
information for computers
This is done by sampling
the wave and storing a
digital representation of
the sound
Sampling frequency is how
often a sound wave is
sampled
Increasing sample
frequency produces a
better quality of sound but
increases file size
Sample rate determines how many
different tones can be represented
High sample rate means more tones
can be represented