What was the price of lettuce in 1928? Were there phone booths on San Francisco docks then?
While these questions are not likely to keep most people awake nights, film-makers, authors, and others grapple with these kinds of memory teasers every day.
One of the most valuable resources in the never-ending quest for answers is the Warner Research Collection, located in Burbank's Central Library.
''If someone is writing a screenplay, they want to make sure the costumes, vocabulary, historical events, and setting are accurate,'' explains library coordinator Mary Ann Grasso. ''You may not be able to visit turn-of-the-century Poland, for example, but we have photos from the 19th century, and illustrations and paintings going back to (prehistoric times).''
Originally part of Warner Brothers Studios, the collection was donated to the City of Burbank in 1975, when Warner Brothers and Columbia Pictures merged to form Burbank Studios. Of course, it's not the only collection here. The Academy Awards Library, perhaps the largest collection of motion picture memorabilia in the world, is nearby.
The Warner Collection is still used by Warner Brothers, but it is also open to the public for a minimum charge of $10 a half hour. Browsing is not encouraged, due to lack of space.
The fee pays for trained researchers who ferret out the desired material from a vast collection of books, magazines, photographs, manufacturers' catalogs, architectural plans, fashion magazines, license plates, newspapers, and more than a million clippings.
Library coordinator Grasso says she can usually estimate how much a particular project will cost a user.
''We also contract with certain television shows and films to read the script and point out historical errors and make sure they don't use brand names, trademarks, or the names and addresses of real people,'' she says. ''We have a list of safe license plates for theatrical use.''
''Annie,'' ''Quest for Fire,'' and ''An Officer and a Gentleman'' are among the films researched recently at the library.
''We have assisted with (the television show) 'Fame' which, although set in New York City, is actually filmed here in southern California at MGM,'' Ms. Grasso says.
''I have a healthy respect for film-makers,'' she remarks. ''So much care is taken to ensure that what appears on the screen is accurate - doorknobs, venetian blinds, street lighting, prices for taxi cabs.''
Barbara Stones used the Warner Collection many times when she was coordinator of the art department at Zoetrope Studios.
''I worked on a film called 'Hammett,' which was set in San Francisco in 1928 ,'' she recalls.
''The script called for (Dashiell) Hammett to make a phone call from a dock, and the director, wanting the call to be surreptitious, wanted him to make it from a phone booth. The question was, would there have been a phone booth on a San Francisco dock in 1928 and, if so, what would it have looked like?''
Mary Ann Grasso did the research.
''We searched our files,'' she says, ''and we also called the Pacific Telephone Liaison Office. They were able to tell us, because they had records of their operations going back that far.''
''The answer,'' Barbara Stones relates, ''was that phone booths weren't in general use at that time. . . .''
''The director decided to put a booth there anyway,'' she says. ''That's an artistic decision. He had the facts and used them as he saw fit.''
''Our art director, Dean Tavoularis, who designed the two 'Godfather' movies, says that atmosphere in a movie helps the audience suspend its disbelief. Any sign or billboard in the background must be from the correct period,'' she observes. ''Otherwise it would look peculiar.
''One major scene (in 'Hammett') took place in a vegetable market. What was the price of lettuce in 1928?''
Ms. Stones is now on the other side of the fence, coordinating the Burbank Library's newly instituted Media Project.
''The collection will take the mystery out of film production,'' she says, ''and show what kind of training is needed to break in and really participate in the industry.''