original_query: How can the amount of light exposing the paper be controlled in different areas?
query: How can the amount of light exposing the paper be controlled in different areas during photographic enlargement?
answer: To control the amount of light in different areas, you can use a mask with a hole to add extra light ('burning') to darken regions, or a small wand to reduce exposure ('dodging') and lighten regions. The tool is kept moving to avoid sharp edges.