ELI5: What Is Lithography?

Lithography is a clever way of printing pictures and patterns onto flat surfaces, kind of like using a magic stamp made of light or oil.

To understand how it works in everyday life, think about what happens when you mix oil and water in a cup: they hate each other and refuse to mix. Traditional lithography uses this simple trick:

• An artist draws a picture on a smooth, flat stone or metal plate using a greasy, oily crayon.
• Next, the whole plate is wiped with water, which only sticks to the empty parts, leaving the greasy drawing dry.
• Finally, oily ink is rolled over the plate. Because oil loves oil and hates water, the ink only sticks to the greasy drawing.
• Press a sheet of paper on top, and voilà—your picture is printed!

• The colorful pages in your favorite storybooks and magazines,
• The cardboard boxes that hold your breakfast cereal,
• The bright posters hanging on your bedroom wall, or
• The labels wrapped around juice bottles,

There is also a high-tech version called photolithography, which uses light instead of greasy crayons. Scientists use tiny beams of light to "print" invisible, super-small mazes and pathways onto shiny slices of silicon. This is how the computer chips inside your smartphone, video game console, and television are made.

Without lithography, we wouldn't have colorful books, printed food packaging, or the tiny brain chips that make our favorite gadgets work!