Final answer:
In drawings, 'ruler lines' (C) are used to create non-printable boundaries or guidelines that help with the overall composition. These assist in providing structure before making permanent lines and are akin to implied lines, which aren't necessarily drawn on the final piece.
Step-by-step explanation:
The non-printable lines that can be used to create boundaries or guidelines in a drawing are most commonly known as ruler lines (C). They are helpful in establishing basic structural composition before any permanent lines are drawn. Ruler lines can be thought of as similar to implied lines, where they are not necessarily drawn on the final piece, but serve as a mental or faint guideline for the artist to create a composition.
Though not directly related to ruler lines, understanding other types of lines enhances one's comprehension of the complexity of line usage in art. Contour lines, like those Albrecht Dürer used in "The Four Horsemen," define the shapes within a piece and can create shading with techniques such as hatching. Additionally, lines can vary in terms of their quality, with geometric or organic lines contributing to the piece's overall feel and suggesting motion, stability, or tranquility.