Noun
A thing belonging or appropriate to a period other than that in which it exists, esp. a thing that is conspicuously old-fashioned.

An act of attributing a custom, event, or object to a period to which it does not belong.

Although an anachronism suggests a specifically set time period and a reference to a thing that is in fact out of place.

Whereas I'm looking more for a piece where the time period is intentionally left vague or ambigious.

Which would lead TO anachronisms

From an old wikipedia entry for the movie:

While the film is set in the present day, it contains many parachronisms. For example, the music playing at the school dance is from the 1980s, featuring "Forever Young" by Alphaville and Cyndi Lauper's "Time after Time". Other vestiges of earlier decades include fashion trends that reflect those of the 70s and 80s, such as Napoleon's moon boots and Deb's side ponytail. The top-loading VCR in the Dynamite residence resembles those from the early 1980s. Throwbacks to the 1990s include music by Backstreet Boys, the Summer's Happy Hands Club performing to Max Martin and Jay Orpin's "Larger than Life", and music by Jamiroquai used in the choreography of Pedro's skits (their song "Canned Heat" is used for the scene in which Napoleon dances). Also, the TV resembles a 1990s model, and some of the shows resemble 1999 pop culture, especially the exercise commercials. The type of imitation Tupperware Uncle Rico is seen selling door-to-door has not been available for purchase for many years. The grandmother's house phone, a slim-line wall-mounted telephone with 25 foot extension cord was first available in the early 1970s. Kip does use the Internet for dating and Rico uses it to purchase a "time machine". However, the style of computer is arguably from the mid- to late- 1990s, and he uses a dial up internet service that charges users by the minute, a practice uncommon in the U.S. in the late 1990s. The music playing in the Pontiac is the 80's funk song "So Ruff, So Tuff" by Zapp & Roger. Finally, Napoleon's school ID card, as shown in the opening credits, clearly reads "2004/2005", unambiguously setting the movie in the present day, despite the film's abundance of elements suggesting otherwise.

That's how they inserted Tom Hanks into historical film segments in "Forrest Gump" and how they created the illusion that Spock entered the elevator from the hanger deck and exited into the bridge without breaking the sequence.

Besides, the mid-80's clothing styles are rather popular now. I doubt that's why the movie appears that way, but I have noticed the throwback.

He was talking about the mixing of various time eras that are used to create a film. This is not via F/X, but through the use of items, stories, styles and music from mixed eras. Forrest Gump mixed eras through special F/X using old footage combined with current time. ND used various hairstyles, technology, etc. to create what the director wanted to use to impart his semi-biography of his Morman upbringing.

But I recently watched Twin Peaks for the first time (despite living less than 10 miles from the place it was filmed when that was on), and I thought I was struck by what I thought was the 1950's look of many of the kids. I assumed this was a conscious device by David Lynch to make us feel out of sync with reality, but when I read reviews about it, people hooted in derision about the "90's hairstyles" so what do I know?

Trying to find words to define Lynch's film making devices is futile.

I can't believe I waited this long to see it -- I thought it was fantastic!

and have your mind blown. A viewing of "Blue Velvet" will also change lives.

That looks really interesting, I'll have to go check that out!

I've got the Blue Velvet DVD, and in fact, it's been all ripped to the hard drive and ready to watch for months. Thanks for the reminder -- I might watch that tonight.

I'm thinking of Donald Sutherland's hippie character in the WWII movie Kelly's Heroes.

I remember hearing that when they wrote West Side Story they created their own street slang so it would never sound dated.

This is an anecdote. I don't know if there is a general term for this kind of device.

Peace, -tg