In a still life painting, every object’s color is affected by the colors of the objects around them. . . but white objects are affected more than most, which can make them very difficult to paint.
In the following video, Craig Nelson explains his process for painting two white eggs. He starts by analyzing the reflected colors that appear in the shadows of the eggs, then works his way towards the lightest color (a nearly pure white). Along the way, he includes tips for naturally blending the paint. Take a look: