The document discusses two techniques used during the Italian Renaissance to create realistic depth in artwork: atmospheric perspective and mathematical perspective. [1] Atmospheric perspective makes distant objects appear lighter, less detailed, and cooler in color to mimic how the atmosphere affects vision. [2] Mathematical perspective uses principles of geometry like vanishing points and lines of perspective to represent three-dimensional space on a two-dimensional surface. [3] Examples like the Mona Lisa and The Last Supper show how artists like Leonardo da Vinci masterfully employed both techniques.