International Klein Blue

#001BB4

About International Klein Blue

International Klein Blue (IKB), also known as #001BB4, is a deep ultramarine blue hue first mixed by the French artist Yves Klein. Klein sought to create a color that embodied his concept of pure space and boundless energy. He patented the color in 1957, ensuring its unique status in the art world. IKB achieves its remarkable vibrancy through the use of a synthetic ultramarine pigment suspended in a clear, matte synthetic resin. This combination allows the pigment to retain its luminosity and intensity, setting it apart from traditional blue paints. The color is often associated with depth, transcendence, and the infinite. In the RGB color model, #001BB4 consists of 0% red, 10.6% green, and 70.6% blue. Its distinctive quality and historical significance make it a striking and memorable color in various creative applications.

The hex color #001BB4, also known as International Klein Blue (IKB), presents significant accessibility challenges, particularly in web design. Its extremely dark hue results in very low contrast against typical light backgrounds, such as white. This low contrast can make text and other elements difficult to read for users with visual impairments, including those with low vision or color blindness. According to WCAG guidelines, sufficient contrast ratios are crucial for ensuring content is perceivable. For standard text (size 14 regular or 12 bold), a contrast ratio of at least 4.5:1 is recommended. For large text (size 18 regular or 14 bold), a contrast ratio of at least 3:1 is advised. Given the darkness of #001BB4, achieving these ratios requires using very light text colors, and even then, careful consideration is needed. It is crucial to test color combinations with accessibility tools to ensure compliance and provide an inclusive experience for all users. Furthermore, providing alternative styling options for users to customize their viewing experience can greatly enhance accessibility.

Shades

Digital Color Formats

RGB
0 27 180
RGB0 27 180
Red
Green
Blue
HSL
231 100% 35.29%
23110035.29HSL
Hue
Saturation
Lightness
HWB
231 0% 29.41%
231029.41HWB
Hue
Whiteness
Blackness
hex#001BB4
rgb0 27 180
hsl231 100% 35.29%
cmyk100% 85% 0% 29.41%
hwb231 0% 29.41%
xyz8.63 4.08 43.51
CMYK
100% 85% 0% 29.41%
10085029.41CMYK
Cyan
Magenta
Yellow
Key
XYZ
8.63 4.08 43.51
8.634.0843.51XYZ
X
Y
Z

Alternative colors

Applications

Complementary color

Buttons

HexColo.rs © 2025