What does "colour depth" refer to in an image?

"Colour depth" refers to the number of bits used to represent the color of a single pixel in an image. This measurement directly affects the range of colors that can be displayed. For example, with 1 bit per pixel, you can have 2 colors (usually black and white), whereas with 8 bits per pixel, you can represent 256 different colors. As the number of bits increases, the total number of possible colors increases exponentially; 24-bit color depth allows for approximately 16.7 million colors, which is sufficient for most photographic images.

Understanding color depth is crucial for graphics and image processing, as it influences the quality and fidelity of images displayed on screens, as well as the way images are stored in digital formats. This concept is foundational in areas like digital imaging, computer graphics, and web design, where color quality is significant.