The number of bits used to represent each sample in digital audio or pixel in digital images, determining the theoretical dynamic range and color depth of digital media.

Bit Depth

Bit depth, also known as color depth in imaging or sample depth in audio, defines the precision with which digital information is stored in binary format. It represents the number of discrete levels available to represent each sample or pixel value.

In Digital Audio

In digital audio systems, bit depth determines the number of possible amplitude values that can be assigned to each audio sample:

16-bit: 65,536 possible values (common for CD audio)
24-bit: 16,777,216 possible values (professional audio standard)
32-bit float: Nearly infinite dynamic range (used in modern Digital Audio Workstation systems)

The relationship between bit depth and dynamic range follows the formula: Dynamic Range (dB) = 6.02n + 1.76 (where n is the bit depth)

In Digital Imaging

For digital photography and computer graphics, bit depth defines the number of colors or shades that can be represented:

8-bit: 256 levels per channel
16-bit: 65,536 levels per channel
32-bit: Used primarily in HDR Photography and professional color grading

Common color depths include:

24-bit (8 bits × 3 channels): "True Color" with 16.7 million possible colors
48-bit (16 bits × 3 channels): Professional imaging standard

Technical Implications

Higher bit depths offer:

Increased Signal-to-Noise Ratio
Smoother Color Gradients in images
Greater flexibility in Post-Processing
Reduced Quantization Error artifacts

However, increased bit depth also results in:

Larger file sizes
Greater processing requirements
Data Storage considerations

Historical Development

The evolution of bit depth capabilities mirrors the advancement of Digital Storage and Processing Power. Early digital systems were limited to 8-bit or lower depths, while modern systems routinely handle 32-bit and higher precision.

Applications

Different contexts require different bit depths:

Consumer media: Usually 16-bit audio, 24-bit color
Professional production: 24-bit audio, 48-bit color
Scientific imaging: May use even higher bit depths for specialized applications

Understanding bit depth is crucial for: