In publishing, any periodical, or regularly-published publication, containing a mix of staff-written or freelanced articles and features, usually pertaining to one particular subject. Magazines may be slick and colorful, or they can be black-and-white and less elaborate. They also usually contain some quantity of photographic content. Most magazines also obtain the bulk of their revenue from the selling of advertising space. The point at which a newsletter becomes a magazine is blurry, but the latter tends to be less slickly and expensively produced, and relies less on advertising than subscription fees for revenue.