The main difference between Steel Blue and Slate Blue is hue — Steel Blue is a cool blue, while Slate Blue is a cool purple. Steel Blue (#4682B4) and Slate Blue (#6A5ACD) are similar colors often confused. They differ in brightness, saturation, and undertone, making each better suited for different design contexts.
Four real design scenarios, with the recommended pick based on hue, saturation, and WCAG contrast.
Slate Blue is more saturated (53% HSL vs 44%) so it reads as bolder and more memorable at logo scale, while Steel Blue can feel washed out when printed small.
Slate Blue hits a 5.31:1 WCAG contrast against white — safer for text-heavy interfaces — where Steel Blue only reaches 4.11:1 and risks failing AA at small body sizes.
Slate Blue is a cool-leaning tone that flatters spring/summer collections and warmer skin undertones, while Steel Blue leans cooler and is better suited to autumn/winter layering.
Steel Blue is the more muted of the two (44% saturation) and sits more calmly on large wall surfaces, while Slate Blue's higher chroma can overwhelm a room when used beyond accent pieces.
Steel Blue (#4682B4) is a medium, moderately saturated blue with a cool undertone — it feels balanced, versatile and balanced in intensity.
Slate Blue (#6A5ACD) is a medium, moderately saturated purple with a cool undertone — it feels balanced, versatile and balanced in intensity.
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.