NEW YORK (REUTERS).- American artist Richard Serra's huge iron sculptures are unique for their sense of movement and apparent simplicity, and so are his drawings.

A new show, "Richard Serra Drawing: A Retrospective," opening on Wednesday at New York's Metropolitan Museum of Art, exposes nearly 40-years worth of the artist's drawings, sketches and works on paper.

"My drawings are seen very infrequently ... so I think for a lot of people who don't know the work, it's probably going to be an eye opener," Serra, 71, told reporters on Monday, adding "I don't mean that good or badly."

The show, which progresses chronologically, is the first to gather the whole span of Serra's drawings, all of which are black and white.

In charcoal drawings on paper from the early 1970's, black shapes are either cleanly defined and starkly geometrical, or have erratic smudges and pencil lines. One 18-part series, called "Drawings after Circuit," consists of thin vertical black lines on yellow paper creating the illusion of a wall of irregular matchsticks.

Other works, painted in solid black with a paint stick on thick linen sheets, are stretched across walls in irregular shapes and angles, like giant swatches of ship sails.

They are at times smooth and slightly shiny, or thick and textured like mottled wool.

"Institutionalized Abstract Art," from 1976, is a painted circle hung high on a white wall resembling a black moon.

A series on paper from 1994, called "Weight and Measure," and also made with a paint stick, juxtaposes the painted surface to the unpainted yellow paper.

Asked about the importance of drawing in relation to his much better known sculpting, Serra said he always carries a sketchbook and draws constantly.

"Your eye is a muscle, you have to keep it in shape and the more you draw, the more you see," he said.

Also included at the show's end are over 25 of the artist's sketchbooks, with drawings he made while traveling in Egypt, Iceland, Peru and other places.

"The notebooks ground people's perception of the work and it gives them an experience of who is this person who is making this work and what his interests might be," Serra said, referring to himself. "What does this guy do when he is in the world, in his daily life?"

The show runs until August 28 and will then travel to San Francisco.

(Reporting by Basil Katz; editing by Patricia Reaney)