I used to give my drawing and illustration students an assignment I called the “white on white” drawing. This is a pretty traditional assignment in any sort of introductory drawing class, which has you draw something like a white egg on white cloth. It introduces the idea that- like nature (or wall paint)-nothing is truly white and that most white objects have some small amount of color in them.

A color that has white in it is referred to as a tint.
A color that has black mixed with it is referred to as a shade.

And the trick to drawing a white object on a white background is to look at the shadows. By drawing the shadows in -and around-the object you can make the white of the paper appear to come forward and create the object.