7/13/09 - Bits, Bytes and Colors

Do you really understand Bits and Bytes?



A bit is a binary digit - the basic unit of information storage. The bit is also a unit of measurement, the information capacity of one binary digit. A single bit is a one or a zero.

1. A byte (abbreviation: B) consists of eight bits

2. A Kilobyte (KB) is 1024 bytes

3. A Megabyte (MB) is 1024 Kilobytes

4. A Gigabyte (GB) is 1024 Megabytes

5. A Terabyte (TB) is 1024 Gigabytes

6. A Petabyte (PB) is 1024 Terabytes

7. An Exabyte (EB) is 1024 Petabytes

8. A Zettabyte (ZB) is 1024 Exabytes

9. a Yottabyte (YB) is 1024 Zettabytes

(Five Exabytes equates to all the words ever spoken; a Zettabyte is the number of all the grains of sand on every beach in the world. Wow!)


So what does all this mean to photographers. The more bits, the more gradation information an image can hold.


A 1-bit, three color (Red, Green, Blue) image contains eight colors. Here is what a color table for a 1-bit color image might looks like:









Picture example:















Color table used for this images:




Here is a 2 bit, three color image:















Color table used for this image:







Finally, here is an 8-bit, three color image:















The color table is too big to show you here.


An 8-bit, three color image (red, green and blue) can also be described as a 24-bit image ... 8-bits for each of the three colors. This means an 8-bit image can contain over 16 million possible colors.


A three color, 16-bit image can contain almost three billion colors.


However, for practical use we can only really see about 7-8 million discrete colors, although a massive color range allows us increased editing elbow room.