Final answer:
The proofreaders' mark '#' signifies the instruction to 'insert a space' in a text, and is a tool used to optimize the readability and presentation of written material.
Step-by-step explanation:
The proofreaders' mark "#" is used to indicate to insert a space in typeset or manuscript text. This mark is important in proofreading to ensure that the text is clean, well-organized, and readable. Other common proofreading marks include those for instructions to capitalize, change to lowercase, insert period, insert comma, insert an apostrophe, insert quotation marks, close up space, transpose letters or words, start a new paragraph, check spelling, move right, and move left.
The proofreaders' mark "#" represents the instruction to "delete" or "remove" a particular content. In the context of proofreading and editing, the "#" symbol is used to indicate that the marked text should be omitted or eliminated. This deletion mark is crucial for editors and writers to communicate changes, corrections, or revisions in a manuscriptWhen a proofreader encounters an error, redundancy, or unnecessary content in a document, they use the "#" mark to signal the need for removal. It helps maintain clarity in communication between authors, editors, and typesetters during the proofreading process.