Trade magazines and other industry literature are key primary sources for the study of film, television, and media history.
These sources are good places to start for many research topics including finding film reviews, ratings and box office data, advertisements, and information about media production and distribution.
Trade magazines are written by industry representatives, and it's not uncommon that an author is not named. Articles are written to share industry information including trends, products, and techniques. Articles in these publications are written for people within the industry using technical language or jargon. References are provided via contextual referrals to other works, and the publications are reviewed by one or more editors employed by the publication.
Popular magazines are written by journalists, or a writer whose specialty is writing, not necessarily in the field that they are reporting. Articles are aimed at a general audience and written without using technical terms, or will define technical terms if used. The articles are reviewed by editors employed by the magazine, and referrals to other works rely on contextual information in the text.
The Media History Digital Library is a free online resource includes early 20th century trade literature -- journals, magazines, press books -- from the histories of film, broadcasting, and recorded sound.
Start with their Early Cinema Collection to browse their holdings of trade and industry literature and popular magazines.
Although some trade magazines are available in full-text through online databases, others are only available through the library in print or on microfilm. Some magazines, such as American Cinematographer (1920-present), can be found on different formats for different time periods of the magazine's publication.
Microfilm: Microfilm Area TR1 .A5335
Online: Performing Arts Periodical Database (1972-present) and Hathi Trust Digital Library (limited)
Directories and Distribution or Rental Catalogs helped programmers, curators, and private collectors find and screen films.
Blackhawk Film Catalogs (USC Hugh M. Hefner Moving Image Archive) - Blackhawk Films was, for many decades, the best source for purchasing rare and important films for home viewing on 16mm, 8mm, and Super 8. USC's collection includes catalogs, many available in PDFs, from 1935-1995.