What is planography based on?

Planography is a printing technique that relies on the principle that water and oil do not readily mix. This fundamental property is what allows for the success of lithography, the most common form of planography. In this process, an image is created on a flat surface where the image areas are treated in such a way that they attract oil-based inks, while the non-image areas attract water. This separation of oil and water creates a clear distinction that allows for accurate reproduction of images through the transfer of ink from the image areas to the substrate, usually paper.

This principle is crucial for the effectiveness of the printing process, as the contrast between the treated and untreated areas facilitates clean and precise prints without smudging or blurring. Understanding the significance of this interaction helps in realizing why planography is distinct from other printing methods, such as relief printing, where raised surfaces are used for ink application, or screen printing, which employs mesh screens for color application.