International Klein Blue

#0421A3

About International Klein Blue

International Klein Blue, often abbreviated as IKB, is a deep blue hue first mixed by the French artist Yves Klein. Klein sought to create a blue that captured the essence of the sky and the sea, achieving a mesmerizing and almost ethereal quality. The color was officially patented by Klein in 1957 to maintain its unique formulation. IKB is notable for its high saturation and vibrancy, making it visually striking and emotionally evocative. The pigment is created using a synthetic ultramarine pigment, and its matte finish further enhances the color's intensity. This specific shade of blue has become iconic in art, design, and popular culture.

The hex color #0421A3, also known as International Klein Blue, presents significant accessibility challenges, particularly for users with visual impairments. Its extremely low lightness value results in very poor contrast against standard white backgrounds, making text or interactive elements nearly illegible. To ensure accessibility, it is crucial to pair this color with significantly lighter hues, aiming for a contrast ratio of at least 4.5:1 for normal text and 3:1 for large text, as per WCAG guidelines. Alternative strategies include using a very light tint of yellow or a bright, desaturated color for text against this blue background. Furthermore, avoid using this color to convey essential information without additional visual cues, such as icons or labels, to accommodate users with color blindness. Careful consideration of color combinations and contrast ratios is paramount when employing this deep blue in design.

Shades

Digital Color Formats

RGB
4 33 163
RGB4 33 163
Red
Green
Blue
HSL
229.06deg 95.21% 32.75%
229.0695.2132.75HSL
Hue
Saturation
Lightness
HWB
229.06deg 1.57% 36.08%
229.061.5736.08HWB
Hue
Whiteness
Blackness
hex#0421A3
rgb4 33 163
hsl229.06deg 95.21% 32.75%
cmyk97.55% 79.75% 0% 36.08%
hwb229.06deg 1.57% 36.08%
xyz-d650.07 0.04 0.35
oklch0.3533 0.204 264.61
oklab0.3533 -0.02 -0.2
CMYK
97.55% 79.75% 0% 36.08%
97.5579.75036.08CMYK
Cyan
Magenta
Yellow
Key
XYZ-d65
0.07 0.04 0.35
0.070.040.35XYZ
X
Y
Z
OKLCH
0.3533 0.204 264.61
0.35330.204264.61LCH
Lightness
Chroma
Hue
OKLAB
0.3533 -0.02 -0.2
0.3533-0.02-0.2LAB
Lightness
Green-Red
Blue-Yellow

Alternative colors

Applications

Complementary color

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