Conversions, palettes, contrast & design ideas for this color.
Color profile
#04252E is a cool color from the Cyan family, closest in name to “Black Box”. In RGB it is rgb(4, 37, 46); in HSL, hsl(193, 84%, 10%).
The color Black Box, with hexadecimal code #04252e, is categorized under the cyan family—a cool, refreshing hue fundamental to CMYK printing. Cyan evokes clarity, focus, and digital innovation, appearing across tech interfaces and futuristic design systems. Additionally, it evokes emotions such as Power, Elegance, Formality, Mystery and Authority. Cyan or blue-green is associated with healing, water, and tranquility. It can symbolize communication and clarity in various cultures. With a high saturation of 84%, this color is intensely vivid—demanding attention and ideal for focal elements like buttons, banners, and brand marks. At only 10% lightness, this extremely dark shade approaches black, delivering maximum drama and contrast when paired with lighter elements. This color is ideal for designs that aim to express Power, Elegance, Formality, Mystery, or Authority. 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
Black Box (#04252E) belongs to the Cyan 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.
Cyan is one of the four foundational inks in CMYK printing, making it literally indispensable to modern publishing. The name derives from the Greek kyanos, meaning 'dark blue,' though the color we call cyan today is distinctly lighter. Ancient Egyptian blue—one of the earliest synthetic pigments (c. 2200 BC)—was close to cyan and used extensively in tomb paintings and pottery across the Nile Valley.
Cyan projects a high-tech, digital-forward identity and pairs naturally with white for clean interfaces or with magenta for vibrant contrast. It works well for SaaS products, data-visualization tools, and creative agencies. Use cyan sparingly on warm-toned palettes, as it can feel cold in those contexts.
Sitting on the cool side of the spectrum (hue 193°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. At 84% 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.
Cyan stimulates mental clarity, focus, and communication. It feels refreshing—like a splash of cool water—making it ideal for apps and services centered on productivity, learning, or wellness. Cyan also carries associations with futurism and digital innovation.
At just 10% lightness, this is an extremely dark shade that approaches black. It is best reserved for text, thin borders, or dramatic full-bleed backgrounds paired with light typography.
Build a dark-mode interface with cyan accent elements (buttons, links, progress indicators) on a charcoal background for a sleek developer-tool aesthetic. Use cyan-to-blue gradients in header sections for SaaS landing pages. In print, spot-color cyan on uncoated paper stock creates a tactile, modern feel.
Every format
Every way to write Black Box — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#04252E
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(4, 37, 46)
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(193, 84%, 10%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(193, 91%, 18%)
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(193 2% 82%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(91%, 20%, 0%, 82%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(24.59% 0.041 219.90)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(24.59% -0.031 -0.026)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 12.90, a: -7.98, b: -9.35
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 12.90, C: 12.29, H: 229.50
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 1.20, Y: 1.55, Z: 2.82
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
271662
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 Black Box.
Percentages show each channel's share of the total light (R + G + B) in Black Box.
Ink coverage
Ink needed to reproduce Black Box in four-color print. Heaviest ink: Cyan.
Print tip: treat these values as a starting point — final output depends on printer profile, paper stock and calibration.
Accessibility · WCAG
How bright Black Box 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 Black Box — per-line copy, or grab the whole block.
background-color: #04252E;
color: #04252E;
border: 2px solid #04252E;
background-color: rgb(4, 37, 46);
background-color: hsl(193, 84%, 10%);
--color: #04252E;
Shades · light to dark
Lighter and darker steps of Black Box — 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 Black Box 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 #04252E — same mood, each with its own character.
Looking for more Cyan shades? Browse Cyan colors →
Inspiration
Curated Unsplash photos that carry the mood of Black Box — hover any tile to download it or view the original.
Good to know
Harmony