Conversions, palettes, contrast & design ideas for this color.
Color profile
#37303D is a cool color from the Purple family, closest in name to “Professor Plum”. In RGB it is rgb(55, 48, 61); in HSL, hsl(272, 12%, 21%).
The color Professor Plum, with hexadecimal code #37303d, 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. At just 12% saturation, this near-neutral shade carries only a subtle hint of its underlying hue, making it versatile for large surfaces and professional contexts. Its low lightness of 21% 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
Professor Plum (#37303D) belongs to the Purple 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.
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 272°), it promotes a feeling of calm distance and intellectual clarity, which is why cool hues dominate corporate identities, healthcare design, and productivity tools. With only 12% saturation, this near-neutral shade carries just a hint of its underlying hue—subtle enough for large surfaces yet adding more warmth (or coolness) than a pure gray.
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 21% 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 Professor Plum — one-tap copy on every format; tap on any card to learn what it is and when to use it.
#37303D
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(55, 48, 61)
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(272, 12%, 21%)
HSL breaks a color into Hue, Saturation and Lightness — the most intuitive way to lighten, darken or mute a color in CSS.
hsv(272, 21%, 24%)
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(272 19% 76%)
HWB blends a pure hue with Whiteness and Blackness — a painter-friendly model added in CSS Color 4 for quick tints and shades.
cmyk(10%, 21%, 0%, 76%)
CMYK is the subtractive Cyan-Magenta-Yellow-Black ink model. Use these values when preparing artwork for a printer or commercial press.
oklch(32.19% 0.025 309.25)
OKLCH is a modern, perceptually-uniform space (Lightness, Chroma, Hue). It powers smooth gradients and accessible palettes in today’s CSS.
oklab(32.19% 0.016 -0.019)
OKLab is the Cartesian form of OKLCH — ideal for blending and interpolating colors without the muddy midpoints older spaces produce.
L: 21.07, a: 6.17, b: -7.04
CIELAB is a device-independent, perceptually-uniform space. It is the standard for measuring color difference (ΔE) and matching across devices.
L: 21.07, C: 9.36, H: 311.22
LCH is CIELAB in cylindrical form — Lightness, Chroma and Hue — letting you adjust vividness and hue while staying perceptually even.
X: 3.47, Y: 3.26, Z: 4.86
CIE XYZ is the 1931 master space that underpins every other model here — the scientific bridge used to convert between color systems.
3616829
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 Professor Plum.
Percentages show each channel's share of the total light (R + G + B) in Professor Plum.
Ink coverage
Ink needed to reproduce Professor Plum 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 Professor Plum 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 Professor Plum — per-line copy, or grab the whole block.
background-color: #37303D;
color: #37303D;
border: 2px solid #37303D;
background-color: rgb(55, 48, 61);
background-color: hsl(272, 12%, 21%);
--color: #37303D;
Shades · light to dark
Lighter and darker steps of Professor Plum — 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 Professor Plum 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 #37303D — same mood, each with its own character.
Looking for more Purple shades? Browse Purple colors →
Inspiration
Curated Unsplash photos that carry the mood of Professor Plum — hover any tile to download it or view the original.
Good to know
Harmony