Indanthrone Blue

A steadfast pigment invented in the 20th century, clear and profound

HEX#2C478B

RGBrgb(44, 71, 139)

HSLhsl(223, 52%, 36%)

HSVhsv(223, 68%, 55%)

CMYKcmyk(68%, 49%, 0%, 45%)

HEXA#2C478BFF

RGBArgba(44, 71, 139, 1)

HSLAhsla(223, 52%, 36%, 1)

OKLCHoklch(65.1%, 0.083, 262)

LCHlch(59.4%, 34.3, 266)

🎨 Color Palettes

Analogous2-3 adjacent hues (≤60°)

Triadic3 hues spaced 120° apart

Split ComplementaryMain color + colors adjacent to its complement

Complementary2 hues spaced 180° apart

Tetradic (Rectangle)4 hues forming a rectangle

MonochromaticSingle hue with varying saturation and lightness

♿ WCAG Contrast Colors

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Aa14px Body

High Contrast Text

#DCE3F4Ratio 6.9:1AA

Suitable for body text, headings, and primary content, ensuring readability for all users

Aa14px Body

Standard Text

#BDB1E7Ratio 4.5:1AA

Suitable for regular body content, meeting WCAG AA standards

Aa14px Body

Large Text / UI Components

#BE7FD7Ratio 3:1AA Large

Suitable for large text (≥18px bold or ≥24px), icons, UI component boundaries

Aa14px Body

Decorative / Dividers

#C74D6FRatio 2:1Fail

Suitable for decorative elements, dividers, non-essential text

📊 Color Scales

Online Color Picker → Gradient Generator →

Lightness VariationFixed hue and saturation, stepwise lightness adjustment ±30%

#0C1427

#14203E

#203365

#2C478C

#385BB2

#5476C9

#7B95D5

Saturation VariationFixed hue and lightness, stepwise saturation adjustment ±30%

#485370

#3E4F79

#354B82

#2C478C

#234395

#1A3F9E

#113BA7

Lightness + Saturation Mixed VariationSimultaneous lightness and saturation adjustment

#1A2132

#1E2843

#273863

#2D4686

#3053AB

#3560D0

#4F78DE

Hue Fine-TuningFixed saturation and lightness, stepwise hue fine-tuning ±15°

#2C5F8C

#2C578C

#2C4F8C

#2C478C

#2C3F8C

#2C378C

#2C2F8C

💡 Use Cases

👗

Classic Qipao

Reproduction Republic-era Indanthrone Blue cotton qipao; the simple blue traces the curves of Eastern women, subtle and timeless.

🪖

Military Uniform Reproduction

In WWII uniform collections and reproductions, Indanthrone Blue is the designated color for Allied navy and air force uniforms.

🎨

Pigment Collection

The tube of artist-grade Indanthrone Blue oil paint is the deepest, most stable dark blue option on the palette.

🛋️

Sun-Resistant Curtains

The top choice for curtains in sun-exposed rooms; Indanthrone Blue remains as vividly blue as new after a decade in the sun, offering both practicality and aesthetics.

📜 Origin & History

Indanthrone Blue was invented by the German company BASF in 1901, the first anthraquinone vat dye. Its full chemical name is Indanthrone Blue RS. Extremely resistant to sunlight, washing, and chlorine bleaching, its fastness far exceeded previous natural and synthetic dyes, ushering in the era of high-performance pigments.

The name Indanthrone comes from 'Indanthrene,' meaning 'indigo from anthracene.' Although a synthetic substance, it presented a clear and profound blue like a deep lake. Upon its launch, it quickly swept the dyeing industry, adopted successively for workwear, military uniforms, and flags.

In the 1920s, Indanthrone Blue was introduced to China. In the calendar advertisement paintings of Shanghai, modern girls wearing Indanthrone Blue qipaos became an era icon. The Soong sisters particularly favored Indanthrone Blue cotton qipaos, which consequently acquired the reputation of being associated with the Republic of China's first family.

During World War II, Indanthrone Blue was extensively used in military uniforms worldwide. Both the US Navy and the British Royal Air Force chose uniforms dyed with Indanthrone. Its never-fading characteristic was crucial in the wartime environment, also endowing it with a color character of resilience and fortitude.

After the war, Indanthrone Blue gained attention in the art world. Yves Klein tested numerous pigments to create his International Klein Blue, and Indanthrone Blue was considered for its high purity and durability. Today, artist-grade Indanthrone Blue oil paint remains an important color in high-end paint brands.

🧠 Color Psychology

Persevering and UnyieldingThe chemical sense of stability, never fading, gives a person the tenacious will to never retreat and remain consistent in adversity.

Clear and ProfoundA blue like a bottomless but impurity-free deep lake, representing purity and depth of thought and character.

Reliable and LoyalIts origin in military and workwear guarantees the quality of kept promises, establishing long-lasting, stable trust relationships.

Nostalgic for the Republic EraRetro imagery associated with the qipao era, evoking gentle remembrance of old Shanghai's elegance and family memories.

Pragmatic RationalityAn industrial color born from functional priority, cultivating a practical, unadorned mindset that values inner quality.

Standardized RigorExtremely high fastness means uncompromising standards, inspiring awe for process norms and quality control.

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