Watching the animated abstract films at the Harvard Film Archive this weekend will not be easy. Over the course of five days, 70 years' worth of work--140 films by dozens of artists--will dance across the Carpenter Center screen. The reward for dipping into this impressively curated and unique retrospective is an experience which skates away from verbal description.

From the start, abstract filmmakers sought to use light as a tool for communication without words. Color, movement, rhythm and music make up the vocabulary of these films. Though they range in length from seconds to 30 minutes, the majority of the films last five or six minutes, the perfect length for the unfolding of one chain of thought.

The archive has done its best to make this event comprehensible by grouping related films together, inviting four authorities to lecture and giving the screenings a more or less chronological sequence. The retrospective opens tonight with an 8:30 screening of "Before Maya Deren: Restored Milestones of American Avant-Garde Cinema," a collection of films from the 1920s and 30s, and ends Monday with Stan Brakhage's 1995 "Hand-Painted Trilogy."

At their best, the films forge new connections in the mind while presenting a complete aesthetic. At their worst, they entertain with bouncy motion and sustain curiosity for the techniques which created them. In between lies a fertile ground of freely-moving shapes which suggest the beginnings of Bauhaus, Pop and MTV-style images.

In fact, the films are often as interesting for what they forecast as what they express. Working in the 30s. Mary Ellen Bute was one of the first to use electronic imagery in film. The spinning, dancing line of her "Mood Contrasts" (1953) seems to embody the music which propels it in a manner reminiscent of the pulsing equalizers which inhabit so many videos. Bute especially wanted to make music visual, to give, as she states in "Rhythm and Light," "a modern artist's impression of what goes on in the mind while listening to music." Bute's witty use of color and shape to express a trumpet's waver or a flute's dropping note make her films especially jolly.

Oskar Fischinger, an exceptional draughtsman and a refugee from Nazi Germany, also celebrated the vocation of music with film. His clean-lined shapes forsake any of Bute's occasional moodiness for a robust interpretation. Fischinger spent hours making the film "An Optical Poem" by filming suspended paper cut-outs. Using a chicken feather on a stick, and the young John Cage as an assistant, he moved exposure by exposure through a film whose vigor belies none of this inch-work. His use of symphony music and the theatrical quality of his compositions lend his short films the feel of Disney's famous concert feature, "Fantasia," which he worked on.

In the 1930s and early 40s, James Davis began working with plastic, fascinated with the new material's ability to reflect pools of light. Experimenting with this quirky, technicolor glare, Davis created films which shift from the geometry of work like Fischinger's towards a more mysterious use of light. His 1961 "Death and Transfiguration" uses light to create twisting forms which play over the similarly twisting torso of a man It's a strange, shifting film, unlike much else in the retrospective.

Evolving attitudes towards the medium of film have resulted in artists whose creativity includes new way of using celluloid Of these artists. Stan Brakhage (whose work is currently in a retrospective at the Museum of Modern Art in New York) is the fore runner. Brakhage hand-paints 8, 16, 35 mm and Imax film stock sometimes using a technique which lets him paste translucent objects onto the film. Brakhage seems to tap into a deep level of emotion by projecting his tiny, beautiful swirls of color onto the large screen. The breathless tension of these intimate films reveals the influence of Davis work.

Easy to enjoy, Hy Hirsch takes the luscious colors of 60s plastics--transparent turquoise hot pink, moody purple--and paints them over real footage of football games, a box of puppies an insouciant cat walking backwards layering that concoction with a jazzy, bluesy soundtrack makes the whole seem like the party scene in "Breakfast at Tiffany's."

The films and filmmakers mentioned above are only a fraction of those featured in the retrospective Others include: Len Iye, James Sibley Watson, Jr. and Melville Webber, James Whitney and Dwinnel Grant. Attending a lecture along with a screening is a good idea, since understanding the technique, milieu and decade in which these artists worked helps make sense of their non objective subjects.

But the films are far from inaccessible, and the occasional moments of jaw-dropping awe make up for any befuddlement or confusion.