They are all hand-printed on handmade paper," he said.
"All the elements are derived with the idea that it is an original print rather than a reproduced work."
The average number of art prints created is 100.
Such numbers may be adjusted according to the agreement with an artist or what the market will bear, he said.
"Some artists who are really precious about what they do will ask for a run of maybe 20 or 30," he said.
Print editions of larger than 100 are often simply reproductions, he said.
"If an edition is numbered at 1,000 or more, I'd be suspicious of that.It's usually offset-printed reproductions. You never make that many prints."
De Soto said the work of many popular 20th-century artists-especially Salvador Dalí, Pablo Picasso and Joan Miró-has been corrupted by large editions of reproductions marketed as signed prints.
An eighth-generation Tucsonan, de Soto left Tucson High School for art school in Los Angeles when he was 17.
He quickly was drafted into the Army Engineers and celebrated his 18th birthday while being inducted.
De Soto's background in art landed him an assignment as a camouflage technician.
After serving in the South Pacific, de Soto returned to Los Angeles briefly and then used money from the G.I. Bill to fund his studies in Mexico.
He studied drawing and painting under such renowned Mexican artists as José Clemente Orozco, David Alfaro Siqueiros and Rufino Tamayo.
In the 50's, he had teaching positions in New York City and Cleveland before teaching lithography, starting in 1959, at the University of Illinois in Champaign-Urbana.
Since then, he has become best known as a lithographer.
He received his master printer's diploma in 1967 from Tamarind Lithography in Los Angeles.
Following that certification, de Soto founded Collectors Press Lithography Workshop in San Francisco (later re-named De Soto Workshop), where he worked until 1993, when he retired to Green Valley.
He still maintains a partnership in a printing workshop in Mexico City while drawing, painting and making prints in a small home studio.
De Soto will appear at a public reception, following a lecture to printmaking students at 4-6 p.m. today at the museum.

Upper Left: "Iron Cross" by Ruffino Tamayo; "Los Papeles de Salazar" by Jose Luis Cuevas; "Payaso" by Alejandro Colunga; All printed as lithographs by Ernest de Soto. (Photo's courtesy Ernest de Soto)

After the edition is complete, the stone is effaced, making future production impossible.
Most artists who use this medium consider their chosen master printer a collaborator-as indispensable as their pencil.
De Soto had that kind of relationship with many of the artists he worked with over the years, he said.
Walking through the UA exhibition recently, he talked about works by Cuevas, Tamayo, and others with the same deep knowledge and pride one would expect from the artists themselves-relating the intricacies of the production of each print as if he had worked on it that morning.

Widely knowledgeable

Not surprisingly, de Soto has a vast knowledge and a keep appreciation for Mexico and its art, and he counts many of the Mexican artist's he's worked with over the years among his closest friends.
"When you see (these prints) you can almost see the region that the artist comes from.
Many of the artists in the collection come from the Mexican state of Oaxaca, a region whose artists, de Soto said, are obsessed with animals.
"In southern Mexico, in the Oaxaca area, they are very animistic," he said. "You can see it in some of the elements of Colunga, and in Tamayo especially. Francisco Toledo is one of the main artists of that region, and you look at his work and you see nothing but scorpions and animals."
Highlights of the current UA exhibit include works by Toledo, Colunga's "Payaso" and "Autobus." Cuevas' "Los Papeles de Salazar," Tamayo's "Iron Cross," and two wonderfully strange prints by Leonora Carrington, one of the few truly Surrealist artists left.

Lent to museum

Most of the prints in this outstanding exhibition were lent to the UA museum by de Soto, part of a personal collection of lithographs he's collected over the years.
Though mostly retired since 1993, spending his days painting and creating lithographs on his home press in Green Valley, de Soto is co-owner of a workshop in Mexico City.
He visits his shop about twice a year, he said, continuing his tradition and reputation for craftsmanship with a new generation of Mexican artists, and keeping up relationships with those he's working with in the past.
De Soto also operates a web site (www.desotowrkshopart.com) through which he offers for sale many of the prints he's made during his long career.
The UA exhibition is free and runs through Dec, 9 at the UA Museum of Art, located on the UA campus near Park Avenue and Speedway Boulevard.