What is the relationship between form and background in brochure design?

In brochure design, the relationship between graphics and background is sometimes called positive and negative phenomenon. Any closed surface is easily considered as a "graph", while another surface that closes this surface is always considered as a "bottom". The relationship between graphics and background is actually the relationship between a closed area and another non-closed background. The smaller area is always regarded as "graphics" and the larger area is always regarded as "bottom". Designers and artists of Aowit can blur the relationship between graphics and background by adjusting the shape, size and layout of graphics on the screen, and transform the relationship between graphics and background on the screen. In China folk paper-cutting, the relationship between positive and negative forms and inversion is more obvious.