A black dominated mix of white and black yields what is called dark gray, it is still sitting between the two opposites. Yet it setting closer to black, meaning it is inheriting some of its features.
Dark gray inherits mystery and complete calmness from black, yet it still keeps some of its unique characteristics such as neutrality and practicality and formality.
How the color is made: in wet media, dark gray is made by mixing two units of black with a unit of white. In RGB color space, it has two-third way of each color 169/255 (~67%). And in CMYK it contains 34% black.
History: gray in general was been used for a long time. It is used in shading of various parts of paintings.
Occurence: Now, we can see it in UI design in both applications and web interfaces.
Color in Action
Unlike gray, dark gray breaks the dullness with mysterious vibe while still maintaining gray's neutrality, authority, and seriousness. And being a dark neutral make the whole color spectrum a good fit for dark gray, especially light tone colors.
Colors that go with Dark Grey
Almost the whole color spectrum is a great fit for not only dark gray but all grays. For example, sky blue, creamy white, beige among other colors are great matches to dark gray.
Dark Grey Color Palettes and Schemes
As other grays, you should not think about the balance of dark gray but rather other colors used in the color palette. But in the case of dark gray, you should pay attention to color weight as dark gray is heavy and should be paired with lighter colors. For example, a sky-inspired palette may contain various shades of blue, white and other shades of grey beside dark gray for shading clouds.
Backgrounds and Seamless Patterns
Dark gray can be used as a background for many kinds of visuals. Yet, when it comes to pattern it is always better to stick with geometric pattern rather than organic ones. Wallpapers can be observed as dull if all colors are shades of gray, yet a slight use of matching colors would create good wallpapers.