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Is True blue cool color?

Is True blue cool color?

True blue is widely considered a cool color. The perception of blue as a cool color is deeply ingrained in culture and language. Phrases like “true blue,” “blue blood,” “blue moon,” and “singing the blues” all conjure cool, calm images. Scientifically speaking, blue light has a shorter wavelength on the visible spectrum, which gives it a cooler temperature. Physiologically, exposure to the color blue has been shown to lower heart rate and body temperature. In interior design and fashion, blue is used to create a feeling of tranquility and relaxation. Looking at the evidence, it seems clear that true blue is universally regarded as a quintessential cool color.

The Science Behind Blue as a Cool Color

On the visible color spectrum, blue wavelengths are shorter than red or orange wavelengths. Shorter wavelengths correspond to higher frequencies and carry more energy. However, while blue light photons have more energy individually, the lower frequency of blue light translates to emitting less heat overall. Thus, blue is scientifically considered a “cool” color, with a cooler temperature than warm colors like red, orange, and yellow.

When we see the color blue, specialized photoreceptor cells in our eyes detect the blue wavelengths of light and send signals to the visual cortex in our brain. The brain interprets and perceives blue as a cool color partly because of its position on the light spectrum.

Interestingly, color temperature and the subjective feeling of warmth or coolness do not always align. For example, violet light has an even shorter wavelength than blue, but we tend to perceive violet as more intense rather than cooler. Our perception is also affected by factors like color saturation and which colors are adjacent to each other. While not a perfect correlation, the spectral position of blue underlies its cool essence.

The Physiological Effects of Blue

Exposure to the color blue can trigger measurable physiological responses in the human body that align with a cool, calming feeling.

Studies have shown that glancing at the color blue for just a few minutes can lower heart rate and decrease blood pressure. These are bodily signs of relaxation, suggesting blue has a tranquilizing effect.

Looking at blue light also stimulates the pituitary gland to secrete more calming hormones like endorphins. The pineal gland simultaneously produces less melatonin, a sleep-regulating hormone. These hormonal shifts indicate that blue light has an uplifting, cooling impact on mood and mindset.

Interestingly, exposure to warmer colors like red has the opposite physiological effects, raising heart rate and exciting the nervous system.

At a fundamental level, feeling cool or warm comes down to our body temperature. Blue appears to directly impact core body temperature regulation in the brain. Staring at blues and greens for prolonged periods can gradually lower internal body heat, while red is more likely to increase it. This cooling bodily sensation further cements the impression of blue as a frigid color.

Blue Symbolism in Language and Culture

Beyond the technical realms of physics and biology, blue also has strong cultural associations with coolness in language, idioms, songs, and more. This ingrained symbolic meaning shapes our instincts around blue as a chilled color.

One of the clearest examples is the expression “true blue,” describing someone extremely loyal or authentic. It conjures imagery of steadfastness and reliability, like a deep blue sea. The origins of “true blue” may come from dyeing fabric with indigo to produce a long-lasting blue pigment.

The idiom “blue blood” refers to nobility and pure bloodlines, again suggesting blue as deep, constant and untainted. “Blue moon” evokes something rare and beautiful in song lyrics and poetry. “Singing the blues” means feeling down or melancholy. Blue is the go-to color to represent sadness and gloominess across cultures.

Various languages also reinforce symbolic links between blue and coolness. In Spanish, “azul” traces back to the Arabic word for lapis lazuli, a vibrant blue gemstone. In Mandarin Chinese, the character for blue is associated with the spring season, trees, and plants emerging from under the cold winter snow.

The Soothing Nature of Blue

With its cultural associations and scientific properties aligned, it makes sense that people instinctively view blue as cool and calming. Applying blue in design and art elicits a peaceful mood and atmosphere.

Interior designers often recommend painting bedrooms blue to promote restful sleep and relaxation. Soft, muted blues are especially popular for creating a tranquil spa-like bathroom. Blue is inherently linked to cleansing water and clear skies, so it feels fresh and open.

Using blue text on websites, posters and e-books has been shown to increase focus and comprehension since it eases eye strain. Blue light filters on phones and laptops aim to prevent sleep disruption by reducing exposure to energizing blue wavelengths.

In fashion, blue denim jeans have embodied casual coolness for generations. More formal navy and cobalt blue clothing also projects confidence without appearing overly imposing or loud. Darker shades of blue work well for police and military uniforms, exuding authority and professionalism.

Across disciplines, blue conjures mental images of calm waters, open horizons, comforting cool breezes – an overall serene state of mind. The natural cool essence of blue makes it an ideal choice for promoting stability and order.

Examples of Blue Representing Coolness

Context Blue Meaning Coolness
Science Shorter wavelength on light spectrum; emits less heat energy
Physiology Lowers heart rate, blood pressure; releases calming hormones
Language “True blue,” “blue blood,” “singing the blues”
Design Soothing blue bedrooms, spas, websites, uniforms


In summary, true blue clearly aligns with coolness across scientific, cultural, and artistic disciplines. Its spectral wavelength, impact on the body, common symbolism, and applications in design all support the perception of blue as a chilled, low-energy color. While personal taste differs, blue’s reputation as a cool color holds up to scrutiny. So the next time you come across something “true blue,” rest assured it is likely both genuine and cool.