macOS Mojave’s Dark Mode is a major feature for late-night computer users. By default, it’s fairly dark. But there are ways of making Dark Mode even darker.
Setting Accent Colors
macOS Mojave chooses the colors it uses for Dark Mode based on the visual environment. As a result, your chosen accent color actually has a visually perceptible (and, indeed, obvious) impact on the color of the user interface. For example, with a bright accent color chosen, the background of the General preference pane is
#474747. With a dark accent color chosen, however, the same background is
#323232, which is noticeably darker. You can compare for yourself in the image. All colors were sampled using Firefox’s eyedropper tool and the system screenshot tool. Measurements should be considered approximate.
Choosing the “Dark Slate” accent color, which is found all the way to the right, will result in the darkest dark mode.
The Effect of Desktop Backgrounds
When we say that Dark Mode uses the colors in the environment to choose its settings, we’re mostly referring to how Mojave’s Dark Mode responds to a desktop background image. Depending on the predominant color in a desktop background, you can end up with noticeably different hues. For an extreme case, we can set a pure white background, then set a pure black background, and then inspect the difference. We can also compare with images of similar hues.
With a white background and a bright accent color, the menu bar of a Finder window is
#363636, and the semi-translucent sidebar is
#5b5b5b. With a black background and dark accent color, the menu bar of a Finder window is
#303030, and the now-solid-colored sidebar is
#2d2d2d. Obviously, the sidebar of a Finder window is where you’re most likely to notice these differences, especially with brightly-colored images as a desktop background.
The Effect of Images
Most people use images as desktop backgrounds, however. What if we set a dark-colored image? In testing, provided that we used a predominantly dark image, interface colors were about the same as with a black background. If there were differences, they were not visually apparent
Once the image became mid-toned or bright, however, interface elements brightened slightly in response. The difference between the darkest picture in macOS Mojave’s built-in dynamic desktop background and the brightest image in that same background was about the same as the difference between white and black backgrounds. The pure white desktop background definitively led to the brightest Dark Mode coloration. Black backgrounds and dark images led to similarly dark colors. Brighter images led to colors close to the pure white background.
There are two other settings that can modify how Dark Mode elements appear on the screen.
Reduce Transparency is found at “System Preferences -> Accessibility -> Display -> Reduce Transparency.”
Like the similarly-named setting on the iPhone, this setting makes translucent interface elements slightly more opaque. This has the effect of making elements like the Finder sidebar slightly less see-through. As a result, desktop background colors (and other elements behind the Finder sidebar) have less of an impact on the sidebar’s color.
The “Increase Contrast” slider is the most dramatic tool we have in our toolkit. Found directly below the “Reduce Transparency” checkbox, it can darken your display to uncomfortable levels. But it’s also a very blunt tool. The difference, unfortunately, cannot be captured by a screenshot, since it is applied as a post-processing effect. It also applies to everything on the screen, which may make it less desirable.
Unfortunately, it’s not possible to darken macOS Mojave’s dark mode by directly editing the colors of the interface. These aren’t simply defined in a plist or something similar: the colors and their reactivity are baked into the user interface at a very low level. But by changing other settings, we can indirectly influence dark mode to be even darker.