Terms such as 'proofreading' and 'copy-editing' can mean different things to different people. Click on the words below to bring up a brief description of what they mean to a professional in the field. They are not always black and white: there are always grey areas in between. And they do not pretend to be comprehensive - it would be a brave man who thinks he could describe everything a copy-editor does, for example, in the space available on this page! But at the very least this page demonstrates the wide variety of work that can be done by proofreaders, copy-editors, indexers, translators...
Technically, a proofreader compares a final document (usually typeset by a typesetter) against the previous version of the document (usually a document which has been copy-edited and therefore has changes marked up on it).
So technically, a proofreader has two documents, one to compare against the other. A proofreader will also look out for and correct obvious errors that might have been missed by the copy-editor; but will leave anything that is not obvious well alone - or will refer to the copy-editor, author or desk editor (or whoever is appropriate) for their attention.
To quote from Chartered Institute of Proofreading and Editing:
...the proofreader reads the proof for consistency in usage and layout, for accuracy in the text and references and for typesetting errors. However, the proofreader is acting only as a quality check, making sure that the copy-editor or typesetter has not missed something. He or she is not responsible for overall consistency and accuracy. Nowadays, straightforward proofreading is quite rare. More and more jobs take the form of a 'blind proofread'.
A copy-editor works to make an author's words clear, consistent, unambiguous and accurate, and at the same time marks up the manuscript for the typesetter.
Clear: the text does not ramble or jump about, and is at the right level for the intended reader.
Consistent: the structure of the text (eg into parts and chapters) is consistent, and the text is consistent in terms of spelling, caplitalisation, hyphenation and so on.
Unambiguous: the wrong meaning cannot be taken from what is written. Frequently this means ensuring correct grammar and punctuation.
Accurate: particularly for non-fiction, no obvious errors have crept into the text, for example inaccurate quotations.
Manuscript mark-up: mark up for the typesetter not only errors to be corrected but also physical attributes of the manuscript, for example its heirarchy of headings, displayed quotations, lists, or the location of footnotes and diagrams.
For a blind proofread, a proofreader works through a final document but, crucially, does not have a previous document for comparison. The proofreader is looking for obvious errors that were either missed by the copy-editor, or which were perhaps marked up by the copy-editor and either missed by the typesetter or performed inaccurately.
To quote Chartered Institute of Proofreading and Editing:
...the proofreader reads the proof for consistency in usage and layout, for accuracy in the text and references and for typesetting errors. However, the proofreader is acting only as a quality check, making sure that the copy-editor or typesetter has not missed something. He or she is not responsible for overall consistency and accuracy. A blind proofread is not the same as a normal proofread, but nor is it the same as a copy-edit. It lies somewhere in between, and a proofreader and a client would need to establish the precise parameters for a blind proofread job before it was undertaken.
Onscreen editing means making or marking up file changes onscreen and not on paper. The two most common ways of doing this are:
a) making changes in a word document, using 'tracked changes' to, in effect, mark up the changes to be made; and
b) marking up changes on a pdf document, using stamps to replicate the standard copy-editing or proofreading marks.
But there are lots of other types of onscreen editing - for example using LaTEX files, or using data pulled from a website.
Translation means simply saying the same thing in a different language. Proofreading doesn't take place, and copy-editing only to the extent that the editor might look out for factual inaccuracies and perhaps better ways of setting out whatever is being translated.
Transliteration is very similar to translation, except that the originating language uses a different alphabet from the target language.
Transcription means to write down spoken words. It is similar to audio dictation, except that when somebody dictates, they are doing so with the full knowledge that someone is going to have to listen to their words and write them down or type them out, and will therefore speak clearly; whereas a transcription may be made of a conversation, or an interview, or court proceedings, where the speakers are not speaking in such a way as to make life easy for the future transriber.
Webpage editing and proofreading means to carry out the usual checks on grammar, spelling and punctuation (and consistency) that would be done on any published material but, depending on the requirements of the client, can also include checking links, checking the navigability of the website,and checking its appearance. Layout onscreen is important for a website, so it may be important to have access to an onscreen version of the site. Often the client will provide just a Word or PDF version of the text, in which case onscreen checks would not be possible. Proofreading and editing a website would not normally include more technical checks on, for example, appearance in search engine listings and SEO (search engine optimisation).
A line edit simply means to go through a document, line by line, looking for the usual suspects of errors in spelling, grammar and punctuation. If the 'line edit' also requires marking up for the benefit of a typesetter, then it is really no different from a normal copy-edit. The two terms are often used interchangeably.
Developmental editing refers to editing that aims to improve the content and structure of a manuscript. Scott Norton, in his excellent book Development Editing writes that 'development editing denotes significant structuring or restrucuring of a manuscript's discourse'. A development editor may not be particularly concerned about spelling, grammar and punctuation; they would want to get the big picture right first. A copy-edit would normally follow a development edit.
Indexing is a skilled profession - it is not just a matter of making a list of important-looking words, names, places, etc and adding them into an index together with a note of where they appear in a book. What words are 'important'? Do you list every instance of their appearance? How is the index to be set out? Are there ways of automating the process so that, if page numbers change, the numbers in the index do too? An editor or proofreader will not normally work on an index (apart possibly from making sure there are no typographical errors in it), although some proofreaders and editors are also trained indexers. You can find out more about indexing at the website of the Society of Indexers.
Typesetting means turning a manuscript, after it has been edited and proofread, into a finished, publishable article. Word is not considered a good medium for final typesetting. Professionals use such programs as InDesign and (especially for technical and mathematical content) LaTEX. Some proofreaders and editors may provide this service, but it is an additional service, not a normal part of a proofread or edit.
Proof-edit is a term that has come into being largely because many independent authors (mainly of fiction) have a rather vague idea of what 'proofread' and 'copy-edit' mean. They want someone to check the usual things (spelling, grammar, punctuation, consistency), but they also want someone to point out problems with the plot, phrases that read oddly, perhaps suggest changes or inclusions. In other words, do more than a proofread, but not as much as a copy-edit. It's particularly important that the remit of a copy-edit is agreed between client and editor, because of its flexible nature.
Project management means to take on a job from inception, through development editing, copy-editing and proofreading, to typesetting. Publishers very often sub-contract this sort of project management, either to a business that specialises in such work, or to individuals. Some editors will take on project management., as another string to their bow. Most do not.
Copywriting is frequently confused with copy-editing, but the two specialisms are quite different. A dictionary definition of copywriting is 'the activity or occupation of writing the text of advertisements or publicity material'. Proofreaders and editors do not usually provide this service.
Writing and rewriting are activities not usually carried out by a proofreader or editor, although a copy-editor will suggest changes or improvements to text during the course of a copy-edit. In particular, no ethical proofreader or editor will (re)write any part of a dissertation or thesis, which should always be the work of the student. More on the ways in which an editor may/may not work on theses and dissertations can be found in the relevant CIEP Guide.
Research is not normally carried out by a proofreader or copy-editor. There may be occasions when a particular project is approached jointly by author and editor, where the editor also has the relevant specialised knowledge so that both undertake some research. But usually an editor will restrict 'research' to occasionally checking a statement that seems off kilter, or looking out missing parts of references, and in both instances the editor ought to confirm that the results are acceptable to the author.