Conversions, palettes, contrast & design ideas for this color.
Color profile
#540684 is a cool color from the Purple family, closest in name to “Indigo”. In RGB it is rgb(84, 6, 132); in HSL, hsl(277, 91%, 27%).
The color Indigo, with hexadecimal code #540684, lands in the purple family, historically reserved for royalty due to the extreme cost of Tyrian dye. Purple activates imagination and spiritual contemplation, blending red's passion with blue's serenity. Additionally, it evokes emotions such as Luxury, Royalty, Spirituality, Imagination and Wisdom. Purple is often linked to creativity, luxury, and spirituality. In Western cultures, it is also associated with ambition and wealth. Indigo and violet have long signified royalty and nobility. With a high saturation of 91%, this color is intensely vivid—demanding attention and ideal for focal elements like buttons, banners, and brand marks. Its low lightness of 27% produces a deep, rich appearance—conveying gravity and luxury, particularly effective in dark-mode designs and premium packaging. This color is ideal for designs that aim to express Luxury, Royalty, Spirituality, Imagination, or Wisdom. 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
Indigo (#540684) belongs to the Purple color family.
This deep, saturated shade conveys authority and richness. Deep tones are favored in luxury packaging, evening-event branding, and dark-mode interfaces where they provide dramatic contrast against lighter elements.
Tyrian purple—derived from the mucus of Murex sea snails—required 12,000 snails to produce just 1.5 grams of dye, making it the most expensive substance in the ancient world. Roman emperors decreed it exclusive to royalty, and Byzantine empresses gave birth in a porphyry-lined chamber so children could be 'born in the purple.' This legacy of exclusivity persists: purple remains shorthand for luxury and prestige.
Purple excels in beauty, wellness, and premium lifestyle branding. Lighter purples (lavender, lilac) suit self-care and floral products, while saturated purples project confidence and creativity. Pair purple with mint green for a fresh contrast, or with charcoal for understated elegance.
Sitting on the cool side of the spectrum (hue 277°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. At 91% saturation, this is a highly vivid color that demands attention. Use it where maximum visual impact is needed—feature banners, accent buttons, and data-visualization highlights.
Purple activates imagination and spiritual contemplation. It blends red's passion with blue's calm, creating a sense of creative tension. In marketing, purple appeals to audiences seeking uniqueness, quality, and a touch of the mystical.
Its low lightness of 27% gives it a deep, intense presence. Deep tones like this excel as dark-mode backgrounds, header bars, and anywhere a sense of gravity or luxury is desired.
Use deep purple backgrounds with metallic gold or rose-gold typography for luxury brand identities. Create purple-to-pink gradients for creative agency hero sections. In app design, purple primary buttons with white text feel premium and distinctive against light backgrounds.
Every format
Every way to write Indigo — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#540684
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(84, 6, 132)
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(277, 91%, 27%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(277, 95%, 52%)
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(277 2% 48%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(36%, 95%, 0%, 48%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(35.69% 0.179 305.66)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(35.69% 0.105 -0.146)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 22.59, a: 51.75, b: -51.05
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 22.59, C: 72.69, H: 315.39
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 7.89, Y: 3.68, Z: 22.12
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
5506692
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 Indigo.
Percentages show each channel's share of the total light (R + G + B) in Indigo.
Ink coverage
Ink needed to reproduce Indigo in four-color print. Heaviest ink: Magenta.
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright 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 Indigo — per-line copy, or grab the whole block.
background-color: #540684;
color: #540684;
border: 2px solid #540684;
background-color: rgb(84, 6, 132);
background-color: hsl(277, 91%, 27%);
--color: #540684;
Shades · light to dark
Lighter and darker steps of 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 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 #540684 — same mood, each with its own character.
Looking for more Purple shades? Browse Purple colors →
Inspiration
Curated Unsplash photos that carry the mood of Indigo — hover any tile to download it or view the original.
Good to know
Harmony