Q. Though the standard Chicago-style proofreading practice is to use the margins to identify all corrections, is there ever an alternate method of proofreading where the symbols and changes are marked only within the text due to margin space issues?
A. In typeset copy (“proof”), there is very little space between the lines, so no, it’s not practical to write corrections there. Not to sound snooty, but good typesetting doesn’t fill up the margins, so it’s rarely a problem that proofreaders have nowhere to write. And it’s important to write or flag every change in the margin, because when typesetters are making corrections, they don’t look for little marks hidden in the lines; they check the margins. (If typesetting is handled offshore, the proofs may be scanned electronically for transmission, in which case your scrunched-in marks might or might not make it through the ether.) If your proofs have very small margins, direct the proofreader to use a colorful pen and flag every interlinear change with at least an X in the margin.