Both editing and proofreading demand close and careful reading, but they focus on different aspects of the writing. Below I describe my understanding and handling of both services.
Editing compares source text to final professionally translated text and ensures proper and consistent use of voice, style, sentence and paragraph construction. During the editing process the editor checks for errors in spelling, grammar and punctuation.
Proofreading deals solely with the final (well-written) text and checks for any remaining errors and inconsistencies in use of grammar, language and format.