Warm white is easiest to judge beside the room’s fixed materials. Tape two samples next to the trim, floor, and largest textile, then watch them from morning to evening.
Tune the atmosphere
Choose the swatch that keeps shadows soft without turning yellow. A sample board you can move around is more honest than a tiny patch hidden behind furniture.
Notice the change
Color is a relationship, so the right white is the one that helps everything else look intentional.