I can't see the thumbs up!
On a light theme the lightest skin tone thumbs up was nearly invisible, and on a dark theme the darkest tone was too; users just could not see it.
Every tone, both themes
We kept the palette and added accessibility hinting to every tone in the emoji set: all five modifier tones and the default yellow. The hinting keeps light tones visible on light surfaces and dark tones visible on dark surfaces.
Emojipedia's changelog for Noto Color Emoji 16.0, dated 10 September 2024, recorded it in one line:
"Tweaked the shading and outlines for most gesture emoji designs."
The design guidance
I art directed the redesign and wrote the design guidance: how each tone is constructed, where outlines and shading provide the contrast, what passes and what fails. That guidance now appears in internal Google-wide docs, so any team drawing, shipping or auditing emoji starts from rules that already pass.
What followed
Gboard's global skin tone setting made the tones easier to use, and the emoji specification, which defines emoji behavior across Google products, now includes the guidance. Jennifer Daniel, writing on The Keyword, described the problem:
"Emoji with the darkest skin tones can be difficult to see in dark mode."