I placed a piece of white printer paper next to a white water bottle. In the first picture, the light is coming from the right side, and makes the paper look as if it has cooler undertones than the water bottle. On the left side of the bottle I notice some grey and blue undertones, and on the right side it seems warmer, but this could be a result of the lighting.
For the second picture I turned all of the lights off. In this picture, the paper looks the same as it did in the first, but the water bottle looks as if it has cool undertones as well.