Originally, proofreading was the late-stage correcting of material that had already been professionally set in type. Proofreading literally means "the reading and checking of proofs" against the original. Today, the term is generally used to mean the final checking of any text-based information. There are two levels of proofreading:
Basic proofreading. In basic proofreading, proofreaders check copy word-for-word against a marked-up draft and identify errors for correction. Basic proofreaders may also check for typographical errors, repetition of small words, and correct styles.
Editorial proofreading. In editorial proofreading, proofreaders also check for errors in word usage (for instance, the use of to instead of too), hyphenation, and subject-verb agreement. If asked, editorial proofreaders can look for grammar problems (using which instead of that). They can also recommend changes in word choice or inappropriate punctuation. Editorial proofreading is usually done on material that has already been edited or reformatted.
Alternatively, copy editors review finished copy for spelling, grammar, consistency, and format. "In many ways, being a copy editor is like taking an English exam that never ends: one's knowledge of spelling, grammar, punctuation, word usage, and syntax is continuously being tested," notes Brunsvold.
At all levels of copy editing, copy editors correct errors, point out conflicting statements to the author, and request advice when the means of resolving a problem is unclear. Throughout all this, copy editors fix whatever is incorrect, confusing, ambiguous, or inappropriate.
Take for example the ambiguous phrase, "Replace the old component." Depending on context, this could mean "Return the old component to its original place" or "Substitute a new component for the old one." After a discussion with the author, the copy editor would rewrite the phrase to clarify the meaning.
Levels of editing
Three levels of copy editing are normally adequate for most jobs: light, medium (standard), and heavy. An additional level, globalization copy editing, is used for information that is likely to be translated.
Light (baseline) copy editing. Light copy editing is very similar to editorial proofreading but does a more thorough check of grammar rules.
Medium (standard) copy editing. Medium copy editing also checks for style consistency and relationships between text and graphics. Table-of-contents entries and organizational problems are also corrected.
Heavy (substantive) copy editing. The main difference between medium and heavy copy editing is the level of judgment and rewriting involved. In a heavy copy edit, editors try to improve the flow of text by rewriting portions to enforce a uniform level, tone, and focus. They change passive voice to active voice and add missing articles (a, an, the). They also rearrange sentences to improve readability. This is particularly true with technical copy. For example, the phrase "hermetic two stage gear drive compressor," is made more readable by adding a bit of punctuation, like this: "hermetic, two-stage, gear-drive compressor."
Globalization copy editing. The globalization copy editor is trained in international and cultural issues and familiar with the challenges that translators face. In addition to all the normal functions of copy editing, globalization copy editing focuses on eliminating ambiguity of any form. The purpose is to make the translation process easier, while working with authors to ensure that changes do not affect technical accuracy of the information. The globalization copy editor also advises customers about aspects of writing that are affected by international publishing of information. This includes characters such as "#" and "&" that do not exist in some languages or have multiple meanings. Another problem area is dates, where 2/5/02 in the United States generally means February 5, but in most European countries, it means May 2.
Both proofreading and copy editing can be valuable to the documents you publish. With a copy editor's ability to make your message clear and a proofreader's eye for detail, your documents will be well respected and professional.