Open Apse Moss
Open Apse Moss (#0B5948) is a deep teal with a jewel character. It carries the deep, saturated richness of a gemstone. Authoritative and slightly formal, it works well for type and heavy UI elements. Its HSL profile (167°, 78%, 20%) places it in the highly saturated band at a dark lightness. Best used in small doses, like logos, CTAs, focus rings, or highlight text, where its saturation becomes a feature rather than noise. For a confident two-color system, pair it with its complementary red. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Old English open, unobstructed — used as a color modifier since the eighteenth century for hues that read as airy or uncrowded. Open blue, open green: moderate saturation combined with optical spaciousness, the slight visual breath of a hue that doesn't crowd the surface it covers. Sits at the crisp-bucket center alongside clear.
Latin absis, vault / arch-recess. As a color modifier, apse implies a semicircular-vaulted-altar-end quality, the visual register of Romanesque-and-Byzantine-cathedral hand-laid mosaic-and-fresco-decorated semicircular altar-end vaulted-apse architectural surfaces under candle-and-incense apse light. Sits at the modifier-and-architecture end of the grid, parallel to nave and aisle in usage.
Bryophyta — the nonvascular plants that colonized land 470 million years ago, before vascular plants and far before flowers. The color refers to a thick mat of Hypnum or sphagnum on a temperate forest floor: a soft, slightly yellow-shifted green with the velvet texture of millimeter-scale leaves. Dustier than fern, deeper than lichen, with the slow patience of a plant that lives by absorbing rain through its surface.
Closest matches
The nearest named color in three reference sources, ranked by perceptual distance (ΔE76 in CIELAB). ΔE < 1 is imperceptible to most viewers; ΔE > 10 is clearly different. When two sources point to the same hex they’re merged into one tile; click any to open that color’s page.
Variations
Click any swatch to exploreHarmonies
Accessibility
How this color appears to viewers with the four major color-vision-deficiency types. Computed via the Machado (2009) physiologically-based model. If a tile matches the original, the color reads the same to that viewer.
The color used as foreground text against pure white and pure black, with the contrast ratio and WCAG 2.1 grade. Aim for AA (4.5:1) for body text and AA Large (3:1) for 18 pt+ headlines; AAA (7:1) is the gold standard for long-form reading surfaces.
Wide gamut
The CSS Color 4 wide-gamut form of this color. Both swatches render the same color on every display — the P3 form only diverges from sRGB when a designer pushes channels outside sRGB's reach.
This color sits well within the sRGB cube. P3 and sRGB share the gray axis and most desaturated tones, so a P3 display renders this identically to an sRGB display.