The connoisseur's playbook for assessing Russian icons hasn't been updated in more than 70 years. Medieval treasures are viewed as artistic masterpieces from a distinct Golden Age. All that came later -- including silver frames studded with jewels, and Renaissance-style renditions of saints amid sumptuous decor -- is evidence of a spiritual art form in decline.

Now comes "Tradition in Transition: Russian Icons in the Age of the Romanovs." The exhibition at Hillwood Museum & Gardens takes an unconventional view. The art form didn't die in 1700, as scholars often maintain -- it evolved.

For evidence, guest curator Wendy R. Salmond presents 43 icons, highly decorated covers and religious books dating from the 18th to the early 20th century. The artifacts were gathered by Hillwood's founder, Marjorie Merriweather Post, and two other American private collectors, all of whom benefited from diplomatic postings in Moscow during the 1930s, when Russian art was selectively made available to westerners in exchange for hard currency.

Post and crew collected "late" icons, meaning they were made long after the so-called Golden Age of the 15th century. Salmond contends that late can also be great. All icons serve as spiritual windows to Heaven. Salmond believes that icons of the recent centuries provide a window on Russian society during its most tumultuous years.

In the changing facial features of a saint, Salmond reads the impact of Peter the Great. The modernizing czar not only banished beards and rough table manners as he imported culture from the West, he also tried to rid Russian Orthodoxy of unsophisticated icon painters. Salmond spots the rise of an elite class in the encrustation of pearls on an image of the Mother of God.

Commercialism, even in a country dominated by peasants, sparked a market for icons mass-printed on color presses. In a darkened hovel, where miracles were needed, what saintly spirit would notice the difference?

An elaborate 1912 icon bears witness to the gap between ruler and subject just before the Russian Revolution. Called the "Mother of God Pledge of Sinners," the icon begins with the traditional painting of tempera on wood. But this small painting -- it measures 5 by 311/16 inches -- was finished with a cover of finely worked gold studded with pearls and emeralds. The Mother of God wears not only a jeweled crown but also a matching double-strand diamond necklace and bracelet worthy of a czarina's birthday ball.

If a fine icon could resemble a bauble from the Faberge workshop, the exhibition catalogue notes that folk icons created in village workshops were being produced by painters known as "God smearers."

Hillwood's exhibition seeks to illustrate how a coherent visual language evolved in the pursuit of modernization. Greek painters gave way to distinctly Russian characterizations, which faltered in the face of western realism, perspective, shading and purely decorative finesse. Some icon makers tried oil paint, in addition to the traditional tempera pigments mixed with egg yolk. During the reign of Catherine the Great, rococo styling flourished.

One branch of the church persisted with old rituals and time-honored renditions of saints, which are still replicated today, and experts aren't complaining. Richard Temple in London, who is considered the dean of icon dealers, responded to a query by e-mail:

"I personally only like the craftsmanship of the 16th and 17th centuries. Later they seem to me too often gaudy and kitsch," he wrote. An icon that "does not fall into the baroque and naturalistic or European style is still powerful, when it conforms to the ancient symbolic and schematic manner."

Gerard Hill, director of Russian works of art for Sotheby's, has no trouble seeing Russia's troubled social fabric reflected in the jeweled icon covers that Post loved to collect.

"It was symptomatic of the whole period," Hill says.

But when considering an icon's value as art, he also returns to tradition.

"I think you can find exquisitely painted icons from this period," Hill says, if only because some late-19th-century workshops were still dedicated to painting in the 14th-century style.

"For the ordinary person who hasn't studied the subject, it is hard to tell the difference," he says. "But the wonderful thing is that you can stand before these two icons, and the icon from the 14th century will move you unconsciously. It has a spiritual essence that will be communicated."

Salmond, an associate professor of art history at Chapman University in Orange, Calif., has studied Hillwood's icons for years. And in this exhibition, she has made the best of a pretty good thing. The two major collections of Golden Age icons are in Russia. Americans such as Post were able to acquire only newer icons.

"In the context of the times, none of these were considered national treasures," Salmond says, acknowledging that bejeweled objects were far too decadent for the Soviet era. "You can either say that's a decline, or you can say, 'My God, how interesting.' "

Post, heir to the cereal fortune of her father, C.W. Post, collected 18th- and 19th-century French and Russian decorative arts. Her interest in Russian works of art began when her husband, Joseph Davies, served as U.S. ambassador to the Soviet Union in 1937-38. Post and Davies began to gather icons, as did Post's friend Frances Wilkinson Rosso, wife of Italian ambassador to Moscow Augusto Rosso. Davies was followed in his post by Laurence A. Steinhardt, who also collected icons. The Steinhardt and Rosso collections enable Salmond to tell her story. Steinhardt collected icons with gilding but also those of the peasantry.

The word "icon" comes from the Greek word for image. Russians inherited icon painting from Byzantium, where it had evolved from a tradition of mosaic and fresco painting in early Byzantine churches. Images and artistic style were originally sanctioned by the Orthodox church as art worthy of spiritual contemplation. Rules dictated how each scene and saint should be depicted, which explains how an archaic style of painting abandoned by the West continues today. It was not until the 14th century that Russian painters Russified the imagery.

By the 19th century, artistry gave way to business. The demand for icons grew with the population, and mechanical reproduction was introduced. Icons were printed, and even imported from Europe. Gold and silver covers were originally made to protect complete paintings. In cheaper modern versions, silver became tin, and painters completed only faces, hands and feet, which showed through. The 1917 revolution halted the production of icons, and workshop painters shifted to papier-mache boxes, decorating them with scenes from folk tales instead of spirits from Heaven.

Even in Russia, icons were not appreciated as art until the era was at a close. In 1901 Czar Nicholas II established a commission for the development of icon painting and donated money to sustain village craftsmen. He also staged a major exhibition of icons in 1913 to mark the 300th anniversary of his family's dynasty. About that time, restorers began cleaning old icons that had been blackened by the smoke of church candles. It had been common practice to repaint icons when the image grew dull. Only when restorers removed the layers did they uncover the rich color and gold leaf associated with icons of the Golden Age. That's when art collectors in the West began to take notice.

So far, Temple says, Russia's new wealthy class is busy buying 19th- and early-20th-century paintings. But he expects that to change once people notice that a legitimate "medieval" icon painted in 1850 can be purchased for a few thousand dollars.

Hill makes a persuasive case for appreciation, whatever the era or cost.

"Russian icons are the great Russian art," he says. "It's not as if they were painting icons as well as other subjects. They were painting icons. This was the engine, the medium of great Russian art."

Tradition in Transition: Russian Icons in the Age of the Romanovs continues through Dec. 31 at Hillwood Museum & Gardens, 4155 Linnean Ave. NW. Reservations required. For details visit www.hillwoodmuseum.org or call 202-686-5807.

"Mother of God Pledge of Sinners" from about 1912, part of the Hillwood exhibition of later Russian icons.Two icons that bookend the age of the Romanovs: Kazan Mother of God, left,

ca. 1600-1650, and Iverskaia Mother of God, ca. 1875-1900.