The first thing you should know about the Eden Hodara "Retrospective," now showing at the National Academy of Sciences, is that the "Valse Triste" is not hung upside down. Eden Hodara wanted it that way, signature upside down in the upper left of the painting and all

That tells you a bit about Eden Hodara. She does not take herself too seriously. How can she? She's from California.

It also tells about the exhibition of 49 of her works from 1955 to 1982. She has not, as she accuses some contemporary artists of doing, developed a "recipe" for her art that she will not change. From one work to another, Hodara changes and her art changes -even up to the moment it is being hung.

That the ingredients change -the media include collage, lithography, paper and acrylics -is not the only way her art evolves. Works go from serious to intriguing, surprising to humorous, and just fun to look at in many cases.

This is Eden Hodara's diary, and it has in it fragments of America's changes as well. The stormy early paintings of the mid-Fifties are huge canvases of bright, demanding colors with segments seemingly torn off to expose expanses of white raw board, Russian newspaper imprisoned under the lacquer barely legible. The Sixties produce the fluorescent op-art with its black and white designs dizzy on eye-hurting orange backgrounds. Later pieces that emulate nature: the powerful sweep of the ocian, the muted but distinct colors of the outdoors.

Her art tells about her. But she elaborates: "I saw a Xerox machine for the first time in the Fifties . . . I saw secretaries marching to machines, feeding them all this information, and it seemed like we were an extension of the machine. I thought, why can't we use this machinery more creatively, make it an extension of ourselves?" Some of the people who find themselves pushing the button on the Xerox machine might appreciate how Hodara has turned the copires, as it were, in, for example, "Mandala for a Clown:" curling clips of Xeroxed designs spilling out in black and white profusion. "The machine-age can be very frightening. The packaging of everything can make you uncomfortable," Hodara says. In this and other works it's gentle humor that tries to make us more comfortable in a world that can be less people and more paper.

There are peaches and pears in her later recipes, soothing watercolors -the fruit in boxes is still nature contained, a sign of a packaged society that can be frustrating, but the beauty of this work, for instance, is what makes the look at the world more tolerable. And in "Caught Shadows I," an acrylic-paper work of 1970, she both masters the packaging and records the times interestingly: take a closer look at what she's lacquered for posterity.

It's fun to watch Hodara change, if only because it is, in a sense, watching all of us change. EDEN HODARA: RETROSPECTIVE -At National Academy of Sciences, 2101 Constitution Avenue NW. Through July 23.