Final answer:
Treating the drawing surface with a solution of gum arabic and acid in the lithographic process divides the surface into positive and negative areas, allowing the ink to adhere to the positive areas and not to the negative areas.
Step-by-step explanation:
The lithographic process is a printing technique that begins by treating the drawing surface with a solution of gum arabic and acid to make it chemically receptive. The gum arabic film, combined with acid, initiates a reaction that divides the surface into positive and negative areas. The positive areas, containing the drawn image, repel water, while the negative areas surrounding the image become water-receptive.
During the printing phase, the gum arabic film is removed, leaving the surface with distinct positive and negative regions. Ink is then applied to the printing surface; it adheres to the positive areas due to their water-repellent nature, creating a mirrored image. This lithographic method allows for the mass production of detailed and high-quality prints, with the positive/negative chemical interaction defining the sharpness and accuracy of the final image.