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Does black and blue make grey?

Does black and blue make grey?

Black and blue are two commonly seen colors that interact in interesting ways when combined. Many people wonder if mixing black and blue makes grey. At first glance, it may seem obvious that combining a dark color like black with a brighter color like blue would result in a muted in-between shade. However, the true results of mixing black and blue paint depend on the ratios used and the properties of the specific pigments. To get a thorough understanding of how black and blue make grey, we need to look at some key questions:

What are the primary properties of black and blue pigments?

Black pigments are dark colors that absorb most visible light wavelengths. The most common black pigments include:

  • Carbon black – Soot or charcoal used since ancient times for ink and paint.
  • Ivory black – Charred animal bones used since the Renaissance.
  • Lamp black – Soot from burning oils, historically used in ink.

Modern synthetic black pigments like mars black also absorb most light. Pure black pigments reflect only about 3-5% of visible light.

Blue pigments get their color from absorbing reddish light wavelengths while reflecting bluer wavelengths. Common blue pigments include:

  • Ultramarine – Made from the mineral lapis lazuli and used since medieval times.
  • Prussian blue – Synthetic pigment discovered in the early 1700s.
  • Phthalocyanine blue – Synthetic organic compound discovered in the 1930s.

Bright blue pigments may reflect over 50% of visible light. However, darker blue shades like navy or indigo reflect less light, making them appear closer to black.

How do black and blue pigments mix?

When black and blue paints or pigments are mixed together, their individual light absorbing and reflecting properties combine to produce a new color. Here is a quick overview of the mixing process:

  • Black pigment continues to absorb most light wavelengths.
  • Blue pigment continues reflecting blue wavelengths.
  • The combination absorbs more red/yellow light than pure blue.
  • This makes the mixture appear darker and greener.

The resulting color is a dark, muted blue-green hue that appears similar to grey. However, it is not a true neutral grey because it retains a subtle blue-green tint.

What ratios make greyish colors?

The exact shade that results from mixing black and blue depends on the ratios used. Here is a table showing example color mixes:

Black Blue Resulting Color
10% 90% Bright blue with a slightly darker tint
30% 70% Darker muted blue
50% 50% Dark blue-grey
70% 30% Grey-blue with subtle tint
90% 10% Nearly black with a faint blue tint

Equal parts black and blue produce a nice balanced blue-grey. But any mixture with more black than blue will appear similar to a standard grey.

How do color properties affect results?

The specific properties of the black and blue pigments used also influence the color mixture results:

  • Darker blue shades mix to greyer colors.
  • More opaque blacks deepen the blue grey.
  • Transparent blacks give a subtler effect.
  • Coarse particle pigments mix less smoothly.

For example, a phthalo blue and mars black mixture will appear very dark grey blue. While an ultramarine and lamp black mix looks slightly brighter and bluer.

The material or medium used to mix the colors also impacts absorption and reflection. Mixing black and blue paint yields different tones than dying black and blue fabric dyes.

Does black and blue make a neutral grey?

While combining black and blue can produce nice greyish tones, the results are not truly neutral greys. A neutral grey reflects all visible wavelengths evenly and lacks any hue bias. True greys are mixed using:

  • Black and white pigments
  • Combinations of primary color pigments
  • Specific grey pigments like carbon black

Any mixture of only black and blue will retain a subtle cool blue-green tint. This may be visible or nearly imperceptible depending on the ratio. But black and blue do not completely cancel each other’s hue properties.

What are common uses for black and blue mixtures?

Although black and blue do not make a perfect neutral grey, their greyish mixes are very useful for many applications:

  • Painting shadows with muted bluish tones
  • Digital art with greyscale rendering
  • Photographic prints and filters
  • Greyscale camouflage patterns
  • Stormy or ominous color palettes
  • Certain fashion and interior design schemes

Black and blue combos work well when a subtle cooler grey tone is desired rather than a warm or strictly neutral effect.


Mixing black and blue pigments does produce attractive greyish tones. But the specific hue achieved depends on the ratios used and the inherent properties of the pigments. While black and blue mixes are not completely neutral greys, their subtle blue-green bias makes them ideal for conveying certain moods and themes. A light touch of blue can bring a grey to life. So black and blue can certainly combine to make interesting versions of grey for artistic and practical uses.