

What does 8bit mean?You can think of computer memory as just a vast number of electronic switches that can be turned on or off. The basic unit of data storage in a computer is called a 'bit'. 'bit' is short for binary integer. A bit represents the state of a switches that is either on — the bit has the value "1" ; or off — the bit has the value "0". More useful data can be represented in a computer by clumping certain numbers of bits together and ascribing a data value to the collective state of the bits in the clump. An 8bit data systemThe simplest data storage in computers uses clumps of 8 bits at a time. JPEG images are 8bit data files. An 8bit system divides data into bunches of of 8 bits. The biggest number is represented when all switches are turned on. on;on;on;on;on;on;on;on = (11111111) The smallest number is represented when all switches are turned off. off;off;off;off;off;off;off;off = (00000000) The next smallest number is represented when all but one switches are turned off. off;off;off;off;off;off;off;on = (00000001) Next is off;off;off;off;off;off;on;off = (00000010) and then off;off;off;off;off;off;on;on = (00000011) ... and so on There are 256 unique combinations of 1 and 0 when arranged this way. Hence we can number the arrangements from 0 to 255. 0=00000000 1=00000001 2=00000010 3=00000011 4=00000100 5=00000101 . 9=00001001
... and so on, up to 255=11111111 using 8bit data we could store all the numbers from 0 to 255, or, more importantly for digital colour, store every value that is on a 256 step scale.
A 16bit data systemData can be represented with greater precision in a 16bit (or even 32 bit) representation. In a 16bit system the smallest number is represented when all switches are off. off;off;off;off;off;off;off;off;off;off;off;off;off;off;off;off (0000000000000000) The biggest number is represented when all switches are on: on;on;on;on;on;on;on;on;on;on;on;on;on;on;on;on ... (1111111111111111) 0 =0000000000000000 1 =0000000000000001 . 9 =0000000000001001 . 83=0000000001010011 . 128=0000000010000000
. 512=0000001000000000 . 1000=0000001111101000 . ... up to 65535=1111111111111111 using 16bit data we could store all the numbers from 0 to 65535 or, more importantly for digital colour, represent 65536 different levels of luminosity, for example.

