The ABC of Photography – Bit
Bit
The basic unit from which any digital piece of data is made. Each bit has a value of either 0 or 1. The sizes of digital files are usually counted in bytes, which are each made up of eight bits. In digital photography, 0 is assigned to black and 1 to white.
Bit depth
Bit depth
The number of bits used to record the colour of a single pixel. Digital cameras usually use at least eight bits for each of the red, green, and blue channels, providing a 24-bit depth, and possible 16,700,000 colours. Many D-SLRs offer higher bit depths when setting to record in raw mode.
The examples below demonstrate the relationship between bit depth and image quality. We’ve taken a small detail of our favorite robot juggler illustration and exported it out at various color depths. The changes will be most obvious in the color gradations of the hat.
24-bit color: 224 = 16,777,216 colors, 45 KB
8-bit color: 28 = 256 colors, 17 KB
7-bit color: 27 = 128 colors, 13 KB
6-bit color: 26 = 64 colors, 10 KB
5-bit color: 25 = 32 colors, 8 KB
4-bit color: 24 = 16 colors, 6 KB
3-bit color: 23 = 8 colors, 5 KB
2-bit color: 22 = 4 colors, 4 KB
1-bit color: 21 = 2 colors, 3 KB
Sample graphic from FCIT’s collection of robot illustrations on the TIM website.
Sources: Pixabay, Wikipedia, Susan Wingfield Lamar High School
