“I do not care how slowly you do it, or with how many alterations, junctions, or re-touchings; the one thing I ask of you is, that the line shall be right”
Accuracy is prioritized over speed and first-pass perfection, making revision and careful measurement legitimate parts of learning a creative skill.
Source details
Lectures on Art, Lecture VI, Project Gutenberg #19164. Ruskin is giving drawing instruction and immediately specifies measurement as the standard of correctness.