Custom Singularity
Custom Singularity (#170605) is a deep red 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 (3°, 64%, 5%) places it in the balanced band at a dark lightness. It works well as a headline, icon, or deep background in an otherwise light layout, pairing cleanly with cream, bone, and warm neutrals. For a confident two-color system, pair it with its complementary cyan. For something softer, pull in its analogous neighbors on either side of the wheel.
Etymology
Latin cōnsuētūdō, habit / usage — adjectival usage of custom. As a color modifier, custom implies a neutral-and-individually-fitted-and-bespoke quality, the neutral color of Savile-Row-tailoring and Gucci-and-Hermès-Made-to-Measure individually-fitted-and-bespoke craft-finish. Sits at the neutral-and-traditional end of the grid, parallel to bespoke and tailored in usage.
Astrophysical gravitational singularity — the central infinitely-dense point of a black hole, where general relativity's space-time geometry becomes formally undefined. Singularity color refers to a Schwarzschild radius event-horizon as visualized in a Penrose diagram: a saturated, slightly cool deep black with the optical complexity of complete light-extinction within the gravitational radius. The deepest theoretical absolute black.
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.