Which of the following is NOT a secondary type/degree of contrast?

Graduation is a term that refers to a gradual change in color, size, or shape, creating a smooth transition rather than a stark contrast. It often leads to a sense of harmony and continuity in floral design and does not highlight differences between elements in the same way that other forms of contrast would.

In contrast, opposition, proximity, and variation all focus on differences that create visual interest and depth within a composition. Opposition introduces stark contrasts between colors or shapes, proximity emphasizes how space and positioning can affect the perception of elements, and variation pertains to the differences in elements that still hold a cohesive relation in size, type, or color.

Thus, graduation does not fit within the framework of contrasting elements, making it the correct choice for what is NOT a secondary type or degree of contrast.