#2188FFPool Water (#2188FF) is a mid-tone, saturated blue with an OKLCH hue of 256°, lightness 0.64 and chroma 0.198. It sits on the cool side of the color wheel. In practice it behaves as an accent color: strong in focal moments, dominant over large fields.
| HEX | #2188FF |
|---|---|
| RGB | rgb(33, 136, 255) |
| HSL | hsl(212, 100%, 56%) |
| HSV | hsv(212, 87%, 100%) |
| CMYK | cmyk(87%, 47%, 0%, 0%) |
| CIE Lab | lab(57.2 15 -66.9) |
| OKLCH | oklch(0.635 0.198 256) |
Under warm 2700K interior light Pool Water shifts noticeably: leans toward purple, loses intensity; in north-facing or shaded light it is virtually unchanged. Overall drift across common illuminants is small (max ΔE ≈ 2.5), so it is a lighting-stable choice.
#3d86f0 — ΔE 2.5, shifts noticeably: leans toward purple, loses intensity#328afb — ΔE 1.2, shifts only faintly, with no single dominant change#2188ff — ΔE 0.0, is virtually unchanged#1d88ff — ΔE 0.1, is virtually unchangedTest Pool Water in the color lighting simulator — sweep it through daylight, warm 2700K light, 4000K LED, and shade alongside the rest of your palette.
Against white it measures 3.48:1 and against black 6.03:1, so black text is the stronger pairing. That pairing passes WCAG AA for body text.
One color explored: close hues with real lightness and chroma structure, so the palette is the anchor through value rather than a set of colors.
#d2e5ff · #8dbeff · #2188ff · #006cd8 · #004a99 · #002b5e
The anchor's neighbours on the wheel — everything shares an undertone, so the chord carries color without anything having to be muted to get along.
#00c2f2 · #00a7f5 · #2188ff · #556be4 · #6650c1 · #6a399b
The mid-gap pairing — sage and mustard, terracotta and olive. A foil rotated 40–65° toward warm or cool: too far to be kin, too near to argue, carried by temperature and a deliberate value offset.
#bb99da · #2188ff · #166bcc · #6f1ca2 · #003570 · #2c0544
One deliberately opposed voice — a single restrained counterpoint across the wheel, or temperature against temperature where the anchor is too muted to carry a loud opposite.
#ffaf07 · #2188ff · #546c8d · #1e4c86 · #032e5f · #001433
The anchor as the only color in the room. True neutrals or complement-warmed near-neutrals let it stay dominant.
#fdf0de · #96a8bf · #2188ff · #786f62 · #1e2f46 · #090300
This color as a ground rather than a subject — its own restraint held across a narrow value band, carrying one saturated voice from the opposite temperature.
#f8f1e6 · #d3cabf · #aaa093 · #382d1c · #170b00 · #2188ff
The opposite hue on the perceptual wheel, tempered to field strength — warm/cool tension without vibration.
#ffefda · #dc9600 · #2188ff · #966500 · #412900 · #00051d
The complement's two neighbours instead of the complement itself — strong contrast with a lower clash risk.
#ffefda · #f58247 · #2188ff · #7a7300 · #501c00 · #050300
Three hues spaced evenly around the wheel; the anchor leads and the other two are held at supporting strength.
#ffeded · #f97784 · #2188ff · #3f8400 · #163800 · #1a0002
Two complementary pairs offset by 90° — the richest chord, kept usable by a strict lightness hierarchy.
#ffecf5 · #eb79bb · #2188ff · #966500 · #003827 · #0f0500
#509CFF · #73AFFF · #93C1FF · #B2D3FF · #D1E5FF
#076FD9 · #0057B0 · #004187 · #002B60 · #00183C
#438BE7 · #5A8DCF · #6E8DB6
Its chroma is high enough to carry accents, calls to action, and focal moments; large fields of it will dominate a composition. In palettes it pairs most predictably with its tonal ramp and analogous neighbors; reserve the complementary hue for small, deliberate contrast.