The term "negative space" simply refers to the empty area surrounding the objects in a painting; you can think of it as the shape that the background takes. One of the interesting things about working with transparent objects is that negative space starts to take on multiple dimensions. For instance, in this painting, there is negative space surrounding the green pilsner glass to the right. Behind that, there is negative space surrounding the creamer. Behind even that, there is the negative space surrounding the rim of the ceramic bowl.