The main difference between Sienna and Rust is brightness and saturation: both are orange shades, but they share similar brightness and Rust is more saturated. Sienna and Rust are often confused but have distinct differences in hue, saturation, and tone. Sienna (#A0522D) and Rust (#B7410E) each suit different design contexts — understanding their differences helps you choose the right color for your project.
Four real design scenarios, with the recommended pick based on hue, saturation, and WCAG contrast.
Rust is more saturated (86% HSL vs 56%) so it reads as bolder and more memorable at logo scale, while Sienna can feel washed out when printed small.
Sienna hits a 5.62:1 WCAG contrast against white — safer for text-heavy interfaces — where Rust only reaches 5.56:1 and risks failing AA at small body sizes.
Sienna is a warm tone that flatters spring/summer collections and warmer skin undertones, while Rust leans warmer and is better suited to autumn/winter layering.
Sienna is the more muted of the two (56% saturation) and sits more calmly on large wall surfaces, while Rust's higher chroma can overwhelm a room when used beyond accent pieces.
Sienna (#A0522D) is a medium, moderately saturated orange with a warm undertone — it feels balanced, versatile and balanced in intensity.
Rust (#B7410E) is a dark, vivid orange with a warm undertone — it feels rich, serious, substantial and bright, energetic, eye-catching.
Text legibility depends on the contrast ratio between foreground and background. WCAG 2.1 AA requires at least 4.5:1 for normal text and 3:1 for large text; AAA requires 7:1. Use these numbers to choose accessible combinations for your design.
Each color has a dedicated page with shades, tints, CSS name, pairings, and color psychology.