What is a matrix?

• A. The glass pane used in stained glass.
• B. The metal surface used in engraving.
• C. The metal surface engraved with dots for stipple engraving.
• D. A wooden printing block.

Answer: (C)

A matrix is the surface that bears the image to be printed and from which ink is transferred to the paper. In stipple engraving, that surface is a metal plate that has been engraved with countless tiny dots; those dots hold the ink and, when pressed, create the tonal variation seen in the final print. This specific description best captures what a matrix is in this context—it's the engravable surface that actually carries the image, not just the material used for stained glass, or a general metal engraving surface, and not a wooden block used in a different printing technique.