Final answer:
The author's tone throughout the passage can best be described as scientific but approachable.
Step-by-step explanation:
The author's tone throughout the passage can best be described as scientific but approachable. The author demonstrates consistent skill in using the technical language associated with visual rhetoric and consistently speaks to the reader in an engaging and professional tone. This is evident in the use of terms like 'line, light, and point of view' and the statement that the author speaks to the reader in an 'engaging and professional tone'.