The main difference between Prussian Blue and Indigo is hue — Prussian Blue is a cool blue, while Indigo is a warm-leaning purple. Prussian Blue and Indigo are often confused but have distinct differences in hue, saturation, and tone. Prussian Blue (#003153) and Indigo (#4B0082) 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.
Prussian Blue is more saturated (100% HSL vs 100%) so it reads as bolder and more memorable at logo scale, while Indigo can feel washed out when printed small.
Prussian Blue hits a 13.43:1 WCAG contrast against white — safer for text-heavy interfaces — where Indigo only reaches 12.95:1 and risks failing AA at small body sizes.
Indigo is a warm tone that flatters spring/summer collections and warmer skin undertones, while Prussian Blue leans cooler and is better suited to autumn/winter layering.
Prussian Blue is the more muted of the two (100% saturation) and sits more calmly on large wall surfaces, while Indigo's higher chroma can overwhelm a room when used beyond accent pieces.
Prussian Blue (#003153) is a very dark, vivid blue with a cool undertone — it feels deep, heavy, grounded and bright, energetic, eye-catching.
Indigo (#4B0082) is a dark, vivid purple with a warm-leaning 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.