The dusty mauve paint chipping off the William Clapp House on Boston Street is not long for this world. Workers are scraping it from the clapboards as they prepare the historic house for a facelift of more neutral tones accented by a rich green. The update is of a piece with a push to educate homeowners on how to paint their historic homes in period-appropriate colors.

Sally Zimmerman of Historic New England, the oldest regional heritage organization in the country and manager of 38 historic houses and museums across the region, spoke about the topic at the Dorchester Historical Society on Sunday, noting that the right paint for a time period can uniquely enhance a house’s character.

“The question comes up, why would you even [worry about historic color]? It’s a house. You can paint it whatever you want; if you’re not in a tightly controlled historic district, nobody’s going to force you to paint your house a certain color,” Zimmerman said. “But it’s a big decision. It’s a very public decision. It costs a lot of money. So, I think from the standpoint of just getting over a big hump, thinking about historic colors with old houses is, to my mind, the way to look at it.”

Before the boom in latex paint in the 1950s and the introduction of thousands of modern precisely-mixed colors, home painting was an artisan craft. Materials were mixed on site, often drawing from natural tones in maybe two dozen shades of basic pigments that varied by region.

Pre-industrial homes primarily featured ranges of yellow ochre, stony gray, and tan for the siding, with sashes that matched the off-white trim in the 18th century segueing to dark greens or blacks in the 19th century. Industrial era homes saw more diversity and richer colors like olive, golds, browns, and maroons for the main house as well as the window sashes. Off-white paints also began to make an appearance on sidings late in the era.

A number of paint brands now feature “historic” palettes, including the California type on which Zimmerman consulted and the Benjamin Moore historical color collection.

If nothing else, Zimmerman said, she hoped prospective renovators learn from the three-color paint-placement scheme. Present thinking involves the darkest color on siding; a complementary color on the trims, i.e., all woodwork that is not siding; and a window sash/door/shutter color. Accent colors are always an option for giving a door some needed pop.

The William Clapp House, the Dorchester Historical Society’s headquarters, was ripe for a color palette update. It is painted in a boutique, vaguely Victorian mauve. After her presentation inside, Zimmerman laid out some options for the society’s consideration:

“The main rationale for switching or looking at some different shades is to incorporate the fact that the front of the house, the porch, and, actually, the dormer above it were modified,” she said. The 1806 building gained newer touches in the 1860s and 1870s. Drawing from natural pigments common during the Civil War era, she recommended pairings of darker greys and taupes with lighter natural trims. The darker green is “a very classic color for shutters and window sashes,” Zimmerman said, softer than an also-acceptable black. “It’s wanting to take what is essentially a Federal house and have colors that would work for the Federal period and the Italianate style,” she added. “Luckily, they’re not wildly different.”

There is a distinction between painting in period-appropriate colors and trying to figure out the original paint color for a particular building.

Restoration requires scientific study, Zimmerman said, while renovation and rehabilitation do not. Boring through layers of old paint to bring a house to its precise former state is rarely a homeowner’s priority, but it can be necessary if the structure serves as a museum.

One of Historic New England’s properties sits across from the Thomas J. Kenny School on Oakton Avenue in Dorchester. The Pierce House, which is open for tours a few times a year, is “one of the last surviving examples of 17th century architecture in the city of Boston,” according to the historic group’s website.

Surveying common paint tones from that era is perfectly appropriate for a historically minded renovator.

Importantly, there is no “correct” home color scheme, Zimmerman said, but a house’s exterior has an impact on the way residents view properties from earlier eras. Painting a historical house in wild neon splashes can serve to make old homes seem silly or undervalued, she said, but a street filled with well-maintained and cohesive houses can offer a psychological boost for the neighborhood and the homeowners.

“You live inside your house,” she said with a grin. “The rest of us have to look at it.”