Slate blue is a dark grayish-blue color that has similarities to both blue and gray shades. While there is some debate around whether slate blue should be classified as a blue or gray, most color experts and designers categorize it as a cool-toned blue with strong grayish undertones.
The Origins of Slate Blue
The first recorded use of “slate blue” as a color name in English was in 1753. It was originally used to describe the bluish-gray color of slate stone. Slate is a fine-grained metamorphic rock that has been used for centuries for applications like roof shingles and chalkboards.
The slate rock gets its typical blue-gray color from its mineral composition. Slate contains high amounts of quartz, muscovite mica, and chlorite minerals. These minerals lend a dark bluish-gray color to the slate.
Over time, “slate blue” emerged as a popular color name not just for the stone, but for similar blue-gray paint colors. It entered widespread use as a color name in the 19th century as synthetic blue pigments were developed that could produce slate blue colors.
Definitions of Slate Blue Color
Authorities differ slightly on how they technically define the slate blue color in color models like RGB and CMYK. Here are some common definitions:
- RGB: 106, 90, 205
- Hex Triplet: #6a5acd
- CMYK: 69%, 100%, 18%, 0%
- HSV (Hue, Saturation, Value): 248°, 39%, 80%
As these color specs show, slate blue is made by mixing a strong blue color with a high amount of black or gray. This gives it a dark muted appearance.
Slate Blue vs. Blue and Gray Shades
Here’s how slate blue visually compares to some pure blue and gray shades:
| Color | RGB Code | Visual Example |
|---|---|---|
| Slate Blue | 106, 90, 205 | |
| Navy Blue | 0, 0, 128 | |
| Blue | 0, 0, 255 | |
| Gray | 128, 128, 128 | |
| Charcoal | 54, 69, 79 |
As you can see, slate blue is much darker and muted than pure blue shades. It also has more blue undertones than neutral grays like medium gray. Compared to darker, cool-toned grays like charcoal, slate blue has a noticeably bluer cast.
How Designers Classify Slate Blue
Most designers classify slate blue as a shade of blue rather than gray. However, they recognize its strong grayish undertones.
On the traditional color wheel, slate blue is located between blue and blue-violet, but very close to the violet side. This means it has strong cool undertones trending toward gray/black, rather than warm reddish undertones.
In color psychology, slate blue is considered to represent qualities like intelligence, dignity, stability, and conservatism. This is similar to how dark gray shades are viewed.
Slate blue is included as a tertiary color in many color harmony formulas like triadic and split-complementary schemes. This means it’s viewed as a variation of blue.
However, in color theory terms like shade and tint, slate blue would be classified as a shade of blue. Adding black or gray to a pure color creates a shade.
Uses of Slate Blue
Here are some of the most common uses of slate blue:
- Web design: Slate blue is a popular conservative background color for websites, especially corporate or finance sites looking to project professionalism.
- Fashion: Slate blue is commonly used in fashion for uniforms, suits, and formalwear. It adds a touch of style and color while remaining professional.
- Home decor: In home decorating, slate blue is used as an accent color in spaces like studies, offices, and bathrooms. It has an elegant, tranquil effect.
- Cosmetics: Slate blue is sometimes seen in makeup for eyeshadow and eyeliner. Paired with neutrals, it creates a subtle, smoky effect.
- Logos: Companies that want to project reliability, trust, or professionalism sometimes incorporate slate blue into their logos.
Slate blue is particularly popular in fields like business, law, academia, and government where traditional, sophisticated branding is desired. It walks the line between feeling modern yet classic.
Slate Blue vs. Air Force Blue
Air Force blue is a similar bluish-gray color that sits near slate blue on the color wheel. Sometimes the names are used interchangeably, but technically they refer to different shades.
Air Force blue is brighter and has more blue content. It was formulated to match the uniforms of the United States Air Force. Slate blue is darker and has more gray content.
However, they are closely related colors and work harmoniously together in designs. Their color specs are:
| Color | RGB | Hex |
|---|---|---|
| Slate Blue | 106, 90, 205 | #6a5acd |
| Air Force Blue | 93, 138, 168 | #5d8aa8 |
Conclusion
While slate blue sits on the fence between blue and gray shades, most design professionals consider it to be a dark blue with strong grayish undertones. It functions as a shade of blue in color theory terms, but also has similarities to dark, cool-toned grays.
Slate blue straddles these two color families, creating an elegant, conservative tone. Its balance of gray and blue makes it universally flattering. This versatile bluish-gray can bridge the divide between warm and cool palettes.
So while there’s no consensus on whether slate blue is strictly a blue or gray, its beauty lies in its split identity. Slate blue brings out the best qualities of both colors – the modern sophistication of gray merged with the refreshing vibrancy of blue.