The light hits it differently. It is reflecting different things.

We had our house repainted, by the same painters and with the same colour (Shaker Beige). I was in the kitchen with the painter and told him the colour it was originally painted, which he verified with the fan deck. Then we moved into the hallway and he asked me if I knew what colour it was. It was the same colour.

The upstairs and downstairs hallways (all Shaker Beige) look different because the upstairs hallway has a big window. The colours look different when the trees have leaves, compare to winter when the trees are bare. And when our Japanese Cherry trees are blooming pink, the walls that face the window look pink too.

I'm guessing that your wall faces a window, and the ceiling faces a dark floor.

Thank you. Yes you're exactly right. The wall faces a window and the ceiling faces a dark wood floor. Wow, who knew that could make such a difference? I guess it'll be pretty difficult to get paint that looks the same on the wall and the ceiling then...

I wouldn’t want anything that dark on my ceiling. I’ve always left ceiling white except for bathrooms, but i’ve seen some people here recommend lightening the color (ie 25-50%) for the ceiling. that may work for you?

https://www.kylieminteriors.ca/paint-colour-review-sherwin-williams-balanced-beige-sw-7037/ If you have north-facing light, you may find Balanced Beige leaning a bit more into that subtle gray, while still holding a soft, passive warmth, which can be a nice balance to cooler northern or afternoon eastern light.

If you add a rug in the room, it will change the colour too. And of course lighting will make a difference.