Digital Colors: Binary and RGB

Digital displays use the RGB color model, an additive system where Red, Green, and Blue light are mixed to create colors. Each of these three colors is called a channel. In a standard system, each channel is allocated 8 bits of memory. Since $2^8 = 256$, each color can have an intensity value ranging from $0$ (completely off) to $255$ (full brightness). When all three channels are at $255$, you see white light; when all are at $0$, you see black.

Writing color values in binary (like $11111111$ for $255$) is tedious for humans. Instead, we use Hexadecimal (Base-16). A 6-digit hex code like #FF5733 is actually three pairs of digits. The first pair is Red, the second is Green, and the third is Blue. Because one hex digit represents 4 bits, a pair of hex digits represents exactly 8 bits (one byte). This allows us to represent the full $0-255$ range using just two characters, from $00$ to $FF$.

Most modern devices use 24-bit color, often called True Color. This means $8$ bits for Red, $8$ for Green, and $8$ for Blue ($8 + 8 + 8 = 24$). To find the total number of possible colors, we multiply the possibilities of each channel together. Since each channel has $256$ options, the calculation is $256 \times 256 \times 256$, or $2^{24}$. This results in over 16.7 million unique colors—more than the human eye can even distinguish!