Just as we explored the concept of how an LED actually creates light in a recent blog on the topic of electroluminescence, we would like to once again explore another slightly technical subject that readers would do well to understand: bit depth. While most people involved in the digital display industry have at least a cursory understanding of the effects of bit depth, many may not fully grasp how it works. Sure, you may know that the greater the bit depth of your display, the more colors it can recreate, but do you know why? What exactly does bit depth represent and how does it work? If these questions intrigue you, keep reading and lets geek out on bit depth!
Enumerating Colors with Zeros and Ones
To start simple, think of a paint-by-number kit. Each color in that kit is assigned a distinct number, say between one and 10 for example. Red may be one, blue may be two, so on and so forth. Well, digital displays work in roughly the same way. Every color still has its own number but the total amount of numbers –and thus the amount of colors- is not a function of how many paints are available in your kit but rather of how many units of digital data processing are available per color channel for each pixel. (For reference, each LED has three color channels, red, green, and blue, within each pixel.) Since digital processors are binary, the units of data your display must process are stored as either zeros or ones. These zeros and ones are called bits and the number of bits a display can process is known as its bit depth. The more bits per color channel a display can handle, the more colors it can enumerate and thus the more colors it can tell its pixels to show.
Spanning 00000000 to 11111111
For example, if a display has a depth of eight bits, that means there are eight bits of data processing available for each color channel, spanning the range between 00000000 and 11111111. There are 256 possible variations within that range and three color channels that possess that range, meaning an 8-bit display with red, green, and blue channels in each pixel is capable of showing 256 x 256 x 256 possible color combinations, a number that totals to be 16,777,216. Most people can only perceive about 10 million colors, so the industry standard for digital displays and cameras is a bit depth of eight bits. High-end photography, cinema, and gaming can require higher bit depths to prevent any banding in over- or underexposed parts of their content, but for most purposes, eight bits will be sufficient. Increasing bit depth will increase the number of colors your display can show, but it will also require greater energy consumption and greater processing power from your software.
If these sort of deep dive definitions are something you find interesting, our latest white paper, Hey! What Does This Spec Mean? clears up the confusion manufacturers have created around several similar terms in the industry. We are also hosting a webinar on this white paper on October 24th so be sure register for that as well!