What aspect of intaglio printing allows the image to be held in place?

Intaglio printing is a process in which images are incised into a surface, typically a metal plate. The technique relies on creating grooves or etched lines that hold the ink. When ink is applied to the plate, it fills these recessed areas. During the printing process, pressure is applied, allowing the ink in the etched lines to transfer onto paper. The etched lines are crucial because they capture and retain the ink, ensuring that the image is both defined and durable in the final print. The precision of these etched lines contributes to the overall quality and detail of the image produced in intaglio printing.

In contrast, other options such as raised surfaces and textured layers are typically associated with different forms of printmaking, such as relief printing. Filling materials can refer to various substances used in different art techniques but do not specifically pertain to how intaglio maintains its image.