Atrium White

On the chip it looks like any other white; on a wall the yellow cast is the first thing you notice. 1020-1 in the PPG range.

Chroma 5.2 is the whole difference: below four a color reads as grey, above ten the yellow cast takes over. At this LRV (85.0), the wall itself becomes a light source of sorts, reflecting daylight back into the room rather than absorbing it.

This is one of the whites where the sample-in-the-room advice actually matters: the yellow cast shifts noticeably between a north wall and a south one. It works as a ceiling color even in rooms painted a different color on the walls, since it keeps the room feeling open from above.

Because this reflects so much light already, a glossier finish can look washed out - flat or matte keeps the white looking intentional rather than stark.

Vista Paint Sierra Blanca (8444) matches it closely enough that no one will tell them apart on a wall. 8 other-brand colors land within delta-E 2 of this one - a well-populated part of the spectrum with several near-equivalents to choose from.

Only 18 of the 1,738 colors PPG makes are lighter than this one. The name is not unique: Behr GR-W2 and Benjamin Moore OC-145 also sell a color called Atrium White, and it is not the same shade. PPG lists it in the 1000 series, alongside 1,736 other colors.