Another way of thinking about a principle is that it is a way of expressing a value judgment on a composition. Each list of these effects cannot be complete, but there are some that are used more often (unity, balance, etc.). If you say that a painting has a unit, you make a value judgment. Too much unity without change is boring and too much variation without unity is chaotic. One of the most common complaints designers have about customer feedback is often customer-centric who say a design should be more “pop.” This seems to be a totally arbitrary term, but what the customer usually means is that the design needs more contrast. Visual design elements and principles describe basic ideas about the practice of visual design. Claude Monet`s still lifes with apples and grapes from 1880 (below) use asymmetry in his design to animate an otherwise mundane arrangement. First, he places the whole composition on the diagonal and cuts the bottom left corner with a dark triangle. The arrangement of the fruit seems to have no plan, but Monet deliberately puts most of it on the top half of the canvas to obtain a lower visual weight. He balances the darker fruit basket with the white of the tablecloth and even lays a few small apples at the bottom right to complete the composition. Diversity is a complement to unity and harmony and is necessary to generate visual interest. Without unity and harmony, an image is chaotic and “unreadable”, without variety, it is blunt and uninteresting.
Good design is achieved through the balance of unity and diversity; the elements must be equal enough for us to perceive them as related and different to be interesting. The harmony of colours, often referred to as “aesthetic measurement”, examines which colour combinations are harmonious and pleasing to the eye and which colour combinations are not.  Color harmony is a major concern for designers, as colours always exist in the presence of other colors in form or space.  A product of satisfactory design is often accompanied by an assortment of colors. Over time, color design tools have been developed to make color harmonization easier for designers.  Design principles will help you carefully plan and organize elements of art so that you are interested and attentive.