Tropical Dream

#d9eae5

A neutral that has no useful hue — it reads as a grey. It is very light — it works as a page background, not as text.

Hex

#d9eae5

RGB

217, 234, 229

OKLCh

92.3% 0.019 176.4°

CIELAB (D50)

91.3, -6.5, 0.4

What is true of this colour, and of no other

45 other named colours sit within ΔE00 2 of it — this part of the space is crowded, and the names here are finer distinctions than most people make.
It uses only 17% of the chroma available at this lightness and hue — there is a far more vivid version of this colour inside sRGB.
As text on white it measures APCA Lc 12.2; on black, Lc -91.8. The sign is the polarity, which the WCAG ratio discards.
Built into an eleven-step scale, 10 of the 10 adjacent pairs stay ΔE00 2 apart — see the ramp.
protanopia and deuteranopia and tritanopia shift it by ΔE00 7.6 and 8.1 and 16.4 — no red cone.

Text on this colour

White text

1.25:1 — fails AA

Black text

16.85:1 — passes AA

Black text is the better of the two at16.85:1. That is enough for body text.

As text on white, it needs to change

#6b7a76 is the nearest colour of the same hue that passes AA on white, at 4.50:1. Only the lightness moved.

Try it against your own background

The same colour, with one cone missing

As you see it

#d9eae5

protanopia

#e8e8e5 · ΔE00 7.6

deuteranopia

#e5e5e5 · ΔE00 8.1

tritanopia

#e2e2ff · ΔE00 16.4

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isReduced Turquoise at ΔE00 0.527: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

Reduced TurquoiseΔE00 0.527 · #daece7
Arctic FlowΔE00 0.573 · #daeae4
WaterscapeΔE00 0.612 · #dcece7
Snowball EffectΔE00 0.614 · #d9e9e5
Aqua BreezeΔE00 0.7 · #d8e8e4
Peaceful NightΔE00 0.782 · #d6e7e3
Dillard’s BlueΔE00 0.793 · #d6e9e4
Dunnock EggΔE00 0.911 · #d9ece6
TranquilΔE00 0.933 · #ddede9
Ice FollyΔE00 1.017 · #dbece9
Ice FloeΔE00 1.034 · #d8e7e1
Lit’l Buoy BlewΔE00 1.091 · #d6e8e1

12 of these have no page of their own: pages exist for the 4,961 colours the dataset marks as good names.