Paper:
DSDN144 Digital Photographics
Info Sheet:
Digital Basics
Pixels and Levels Pixels are small square picture elements that contain colour, greyscale, or black and white information.
Continuous Tone
Ten pixels
These ten pixels, eac=h with a different tone are used to describe the continuous tone above. Each different tone is called a level.
Binary Code A bit (short for binary digit) can either be a one or a zero and is the foundation of a computer’s language. A digital image is just a long string of binary code.
Bit = 1 or 0 Byte = 8 Bits Kilobyte (k) = 1024 Bytes Megabyte (Mb) = 1024 K Gigabyte (Gb) = 1024 Mb Terrabyte (Tb) = 1024 Gb Colour Depth A 1-bit image (1 or 0) contains pixels which can be either on or off (black or white) (21).
1 Bit
2 Bit
A 2-bit image (00, 01, 10, or 11) contains pixels of four values - black, white and two different greys (22 = 2x2 = 4) A 4-bit image contains pixels which can be any of 16 values: (24 = 2x2x2x2=16) An 8-bit image contains pixels which can be any of 256 values (28 = 256). A 16-bit image contains pixels which can be any of 65 thousand values. A 24-bit image contains pixels which can be any of 16.7 Million values. Once we get to this size of colour depth the palette of colours is virtually unlimited.