Conversions, palettes, contrast & design ideas for this color.
Color profile
#51597A is a cool color from the Blue family, closest in name to “Deep Indigo”. In RGB it is rgb(81, 89, 122); in HSL, hsl(228, 20%, 40%).
The color Deep Indigo, with hexadecimal code #51597a, belongs to the blue color family, the world's most universally preferred hue. Blue projects trust, stability, and intellectual calm, which is why it dominates corporate, financial, and technology branding worldwide. Additionally, it evokes emotions such as Trust, Peace, Loyalty, Integrity and Tranquility. Blue signifies tranquility and stability. In Middle Eastern cultures, it can also represent protection against the evil eye, while in Western cultures, it symbolizes calmness and reliability. At just 20% saturation, this near-neutral shade carries only a subtle hint of its underlying hue, making it versatile for large surfaces and professional contexts. With a mid-range lightness of 40%, it offers excellent versatility—readable as text on light backgrounds and visible as an element on dark ones. This color is ideal for designs that aim to express Trust, Peace, Loyalty, Integrity, or Tranquility. It can be effectively used in web design, branding, and marketing materials to attract attention and convey specific messages.
Key facts
The story of this color
Deep Indigo (#51597A) belongs to the Blue color family.
With a dusty, low-saturation character, this color offers quiet complexity—neither bold nor faded. Dusty tones add vintage charm to retro-inspired designs and pair beautifully with metallic accents like copper or brass.
Blue's scarcity in nature made it a late addition to human color vocabulary—Homer's 'wine-dark sea' notably omits the word blue entirely. The breakthrough came with Egyptian Blue (~2200 BC) and later ultramarine from Afghan lapis lazuli, which Medieval artists hoarded for divine subjects. Synthetic ultramarine (1826) and cobalt blue democratized the color, enabling Impressionists like Monet and Renoir to paint blue-drenched landscapes affordably.
Blue is the most universally liked color and dominates corporate branding (Facebook, LinkedIn, IBM, Samsung). Use it to establish trust, competence, and professionalism. Lighter blues suit wellness and social apps, while darker blues convey authority and security. Avoid using blue for food branding—it suppresses appetite.
Sitting on the cool side of the spectrum (hue 228°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. At 20% saturation, the color has a muted, sophisticated quality that pairs well with bolder accents. It works as a background, a border, or a secondary element in layered compositions.
Blue lowers blood pressure and heart rate, promoting calm and focused thought. It signals reliability and integrity, which is why it is the default choice for banks, insurance companies, and government institutions. In UX, blue links and buttons feel intuitive because users have been trained by decades of web convention.
With a mid-range lightness of 40%, this tone is highly versatile: dark enough to serve as body text on white, yet light enough to stand out on charcoal or navy backgrounds.
Pair classic blue (#0047AB) with warm amber for a nautical or heritage brand. Use gradient blues (light-to-dark, top-to-bottom) for app onboarding screens that feel expansive and inviting. In data dashboards, blue is the safest primary chart color—it's distinct, professional, and colorblind-friendly.
Every format
Every way to write Deep Indigo — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#51597A
Hexadecimal is the web’s universal color notation — two digits each for red, green and blue. Drop it straight into HTML, CSS or any design tool.
rgb(81, 89, 122)
RGB is the additive Red-Green-Blue model every screen uses to emit light. The default choice for websites, apps and on-screen UI.
hsl(228, 20%, 40%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(228, 34%, 48%)
HSV (also called HSB) maps Hue, Saturation and Value/Brightness. It is the model behind the color pickers in Photoshop, Figma and most design apps.
hwb(228 32% 52%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(34%, 27%, 0%, 52%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(47.07% 0.055 273.62)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(47.07% 0.003 -0.054)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 38.37, a: 5.38, b: -19.65
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 38.37, C: 20.37, H: 285.30
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 10.48, Y: 10.30, Z: 19.85
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
5331322
The 24-bit integer value of the color — handy for databases, APIs, game engines and low-level graphics code.
Channel breakdown
How much red, green and blue light mixes into Deep Indigo.
Percentages show each channel's share of the total light (R + G + B) in Deep Indigo.
Ink coverage
Ink needed to reproduce Deep Indigo in four-color print. Heaviest ink: Key (Black).
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright Deep Indigo is, and how far black and white text clear each WCAG bar.
Contrast ratio · 1:1 → 21:1 (log scale)
Developer shortcuts
Copy-and-paste CSS for Deep Indigo — per-line copy, or grab the whole block.
background-color: #51597A;
color: #51597A;
border: 2px solid #51597A;
background-color: rgb(81, 89, 122);
background-color: hsl(228, 20%, 40%);
--color: #51597A;
Shades · light to dark
Lighter and darker steps of Deep Indigo — the color's full brightness range in one strip.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 180° apart
Two colors opposite on the wheel — maximum contrast for attention-grabbing accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · adjacent hues
Neighboring hues on the wheel — harmonious, calm combinations that feel unified.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 120° apart
Three colors evenly spaced on the wheel — vibrant and energetic, yet balanced.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Harmony · 90° apart
Four colors evenly spaced on the wheel (tetradic) — rich schemes with multiple accents.
The dot marks the original color. Hover any shade to copy its hex or open its color page.
Accessibility
How Deep Indigo reads across five kinds of color vision — a ✓ Friendly verdict means the color difference stays distinguishable for that vision type.
The dot marks the original color. Hover any shade to copy its hex.
Harmony overview
The lead color from each harmony scheme, side by side — a shortcut to the full palettes above.
Perceptually nearby
A step away in brightness, richness or shade — each still feels like the same color.
From the color-name library
The closest named colors to #51597A — same mood, each with its own character.
Looking for more Blue shades? Browse Blue colors →
Inspiration
Curated Unsplash photos that carry the mood of Deep Indigo — hover any tile to download it or view the original.
Good to know
Harmony