What is in sharp contrast to the color of the contract drawing?

Contrast color is a physiological phenomenon produced by human visual senses, and it is the balance effect of retina on color.

The color opposite to each color (diagonal 180 degrees) in the color circle is called "contrast color (complementary color)". Putting contrasting colors together will give people a strong sense of rejection. If they are mixed together, they will bring out turbid colors, such as red and green, blue and orange, yellow and purple.

Contrast color can also be defined as: two colors that can be clearly distinguished are called contrast colors. Including hue contrast, lightness contrast, saturation contrast, cold and warm contrast, complementary color contrast, color contrast and achromatic contrast. It is an important means to form obvious color effect, and it is also an important method to give color expression. Its form of expression is better than simultaneous comparison and successive comparison. For example, yellow and blue, purple and green, red and blue, any color and black, white, gray, dark and bright, cold and warm, bright and dark are all contrasting colors.

Complementary color refers to the complementary color relationship between a primary color and its corresponding intermediate color in chromatography. There are three primary colors, namely, red, yellow and blue, which are color units that cannot be decomposed any more. The colors produced by each pair of three primary colors are called intermediate colors, such as red and yellow for orange, yellow and blue for green, blue and red for purple, and orange, green and purple are called intermediate colors. Red and green, orange and blue, yellow and purple are complementary colors. Due to the strong separation of complementary colors, in the performance of color painting, proper use of complementary colors in appropriate positions can not only strengthen color contrast, but also show special visual contrast and balance effect.