Kathleen Snowden of New Market started collecting books and newspapers about black Americans more than 20 years ago.

Today, her accumulation of Afro-American memorabilia, stored in cardboard boxes, bureau drawers and stuck under beds, spills over most of her three-bedroom house and into a shed out back.

Marguerite Ross Barnett, chairman of the political science department at Howard University, started collecting 12 years ago after seeing two Sambo figures in a store window in New York. Now she has about 2,000 items --magazines, post cards, coin banks, pencil sharpeners -- most of which show negative, frankly racist images of blacks which typified turn-of-the century attitudes.

These women reflect a growing trend among Afro-Americans who are starting to collect an array of materials -- photographs, books, paintings, newspapers, advertisements, dolls, ashtrays -- about their past. Such activity is relatively recent for blacks who are driven by increasing affluence and black pride.

Whites, according to antique dealers and collectors, have been assembling Afro-American materials for many years. Now people of all colors and ethnic groups are collecting.

The search for black material is part of a larger collecting trend in this country. Some say Americans are the world's most avid collectors, coins to fragments of the White House to varieties of barbed wire. "We collect everything," says Marvin Sadik, director of the National Portrait Gallery. "We started collecting as soon as we stepped on the shores."

Black material is only part of the thousands of pieces owned by Set Momjian, marketing executive from Huntington Valley, Pa. "You didn't need much money to buy this stuff when I started 25 years ago," he says. "Black was not beautiful. Colleges weren't buying the material. When I started, there were no flea markets. Collecting has become big -- profitable for leaders and expensive to collectors." Some of his collection is on loan to the Smithsonian Institution and the Afro-American Museum in Philadelphia.

The trend for collecting Afro-American material, some say, is bigger than it seems. Its effect, however, is hard to gauge because many collectors are unwilling to talk about their materials for fear of making themselves public and becoming vulnerable to burglars.

Nevertheless, these collectors are paying increasingly higher prices for antiques. Post cards with Sambo figures dating from the late 19th century and early 20th century cost $15 or more a piece. Currier and Ives caricatures from the 1860s cost up to $500.

"People thought I was out of my mind when I started collecting," Momjian recalls. "But this material is invaluable. I have a letter written by a southern white to people in Washington. They were writing about hanging blacks in the South to celebrate presidential inauguration. This kind of material tells a lot about us (Americans) and our history."

Other collectors are just as devoted. Kathleen Snowden says, "This is my whole heart. I think about it so much."

"In a way, I've been collecting all my life," says Snowden, head of the Gnotobiotic Unit at the National Institutes of Health, fingering a can of Joe Louis hair pomade dating back to the 1940s. "My mother collects. She got me interested in black history. I got into this when I was just a kid.

Snowden is more than a collector --she's an accumulator. She owns newspapers going back to the mid-19th century (a copy of The Daily Chronicle she has from 1840 contains a story of 700 slaves dying from suffocation on a ship in Mozambique).

The oldest books in her collection date from 1802 and 1813. She owns soldier's payroll records and mustering-out rolls from the Civil War, marriage licenses from the early 1800s and slave manumission papers.

Her assemblage includes plenty of first-edition books by 20th-century black authors such as W.E.B. DuBois, Claude McKay, Richard Wright, Ralph Ellison. And there are dolls, prints, china, political buttons, theater advertisements, slave auction notices.

"Here's a 50-cent piece with Booker T. Washington's face on the front -- I bet you never saw one of those," she says to visitors with a proud smile.

In her Afro-American Gift Shop, which occupies another room in her house, she displays an assemblage of African artifacts -- masks, robes, statuettes. "I just have fun with this shop," Snowden laughs. "It's another way I keep myself busy."

While Snowden concentrates largely on documents and written material most of which are positive, Barnett focuses on items of popular culture -- post cards, advertisements, dolls which convey largely negative images.

Both women plan to use their collections as background for books. Barnett, who views her subject with scholarly detachment, hopes to write two, one a book of photographs and the other "a more academic study, a book of structural analysis of how (negative) images got started and what effect they had."

Snowden's book is planned as a history of blacks in Maryland, utilizing her memorabilia and the tracing of her ancestry back to Africa.

Other collectors are less ambitious. For one, Olive Harris, a former art teacher in Richmond, collects hair-styling items -- straightening combs and irons, mustache curlers, hair-oil containers, hair pullers, wavers.

She has about 40 beauty tools. The remainder of her collection -- books, handmade dolls, sheet music and phonograph records -- is small.

Edna Newton, 87, who was born and raised in Baltimore and has lived in the same house for 50 years, says she has given away most of her collection.

However, she still retains a cup that once belonged to abolitionist Frederick Douglass, a photograph of her father with Douglass, a 100-year-old vase and two cherry pedestal stools made by 19th-century black artisans.

Some collectors also are dealers. Ronald Rooks, 41, owner of Merryman Antiques in Baltimore, says he's been collecting for 20 years and selling for 16.

"As a kid, I started collecting stamps," he recalls. "Then I went on to collect anything that caught my attention -- coins, prints, post card."

At one time he says he owned more than 2,000 Afro-American items. "Now I have only 50 prime pieces," he says. "Here's a nice piece. It's an early print of Bethel A.M.E. Church, one of the oldest black churches in Baltimore."

"I don't collect much anymore. I used to buy everything. Mostly I sell now."

Rooks' Shop, on Baltimore's antique row on North Howard Street, is a crowded, jumbled store filled with paintings, prints, caricatures, books and thousands of post cards.

And his stock is general. "I don't sell just black items," he says, shaking an index finger. "I know about all antiques!"

Dealers like Rooks and collectors such as Snowden and Barnett find their materials in a variety of places --tions and trading with other collectors and dealers.

"Collecting is a whole way of life," explains Snowden. She's so influenced her husband that he looks for items for her.

Barnett says she's reduced her collecting to almost zero in the last two years because of the inflated market. "Once I say what I want to say in a book, I'll stop collecting," she muses.

Collectors like Barnett and Snowden believe the number of blacks collecting Afro-American memorabilia will continue to increase.

Rooks agrees. "Blacks are feeling more at ease about collecting," he notes. "I remember eight or nine years ago it was hard to interest colleges like Morgan (State University) in buying old black material. Then when the black consciousness thing came along, colleges got more interested. But they still weren't buying much.

"I remember I had a whole load of old books. I sold them five at a time to a book dealer.That's the only way I could make a profit. He'd pay $50 for five, but he wanted to pay the same price for 15. Well, he was selling them to Morgan.

"If I had those books now, I could sell them for much more. The people over at Morgan want books like that badly."