Pantry Plum

It is dark enough that the room, not the paint, becomes the thing you notice - though the blue cast keeps it from reading as flat black. 7229, from Vista Paint.

With an LRV this low (7.0), a room relies entirely on its fixtures; the paint gives nothing back. In dim, ambient light this reads as a flat, undifferentiated dark; it takes a direct light source for the blue cast to surface at all.

Next to it, white trim reads brighter and cooler than it does anywhere else in the house - the gap in light reflectance is what does that, not the trim paint itself. A natural scheme here moves in three clear steps: this color on the main wall, a noticeably lighter mid-tone for a second wall or built-in, and a near-white on the ceiling. Each jump should be obvious at a glance, not something you have to squint to tell apart (roughly 7.0, 46 and 85 on the light-reflectance scale, for reference).

On the wall opposite the room's main window, this catches the most daylight available and is the one wall where the color reads true rather than flat. Vista Paint Diamond Heights makes a good second wall color here - different enough to read as a real choice, close enough to still feel related (about 29 points apart in light reflectance).

Eggshell can work if the wall is in excellent condition, but matte is the more forgiving default for a color at the bottom of the scale.

Dunn-Edwards Black Pearl (DEA186) runs close enough - delta-E 1.39 - that swapping brands should not change how the room looks. This is a relatively uncrowded spot in the spectrum - just 1 color from other brands come this close.

Nearly everything Vista Paint makes is lighter than this: 45 of their 2,742 colors sit below it. Vista Paint lists it in the K codes, alongside 1,318 other colors.