Warm Light

#fff9d8

A yellow that is nearly neutral — the hue shows only against a true grey. It is very light — it works as a page background, not as text.

Hex

#fff9d8

RGB

255, 249, 216

OKLCh

97.8% 0.043 98.6°

CIELAB (D50)

97.8, -1.9, 16.7

What is true of this colour, and of no other

40 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 sits exactly on the sRGB boundary: at this lightness and hue the gamut has nothing left, and a wider display would show a more colourful version of it.
As text on white it measures APCA Lc 0.0; on black, Lc -103.3. 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.
tritanopia shifts it by ΔE00 6.9 — no blue cone.

Text on this colour

White text

1.06:1 — fails AA

Black text

19.79:1 — passes AA

Black text is the better of the two at19.79:1. That is enough for body text.

As text on white, it needs to change

#7d775a 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

#fff9d8

protanopia

#fafad8 · ΔE00 2.6

deuteranopia

#fbfbd8 · ΔE00 2.6

tritanopia

#fcfcc0 · ΔE00 6.9

Run a whole palette through all three

The twelve nearest named colours

Ranked by CIEDE2000 — perceptual distance, not hex arithmetic. The closest isCotton Tail at ΔE00 0.464: below 1.0 — an ordinary observer cannot tell these apart, even side by side. What the numbers mean.

Cotton TailΔE00 0.464 · #fff8d7
Wild AppleΔE00 0.556 · #fef9d7
Reddish WhiteΔE00 0.69 · #fff8d5
Frozen BananaΔE00 0.976 · #fbf5d6
Cotton ClothΔE00 1.044 · #faf4d4
Perky TintΔE00 1.071 · #fbf4d3
DaystarΔE00 1.074 · #fff8da
Sweet JasmineΔE00 1.153 · #f9f4d4
Alluring LightΔE00 1.187 · #fff7d8
EffervescentΔE00 1.214 · #fbf4d1
Country SummerΔE00 1.305 · #fffbd7
Rice PaperΔE00 1.381 · #fffcdb

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