The Newburyport ArtWalk is a self-guided tour of galleries that can be done at any time, but there are only four weekends during the year to catch special exhibits, artist discussions, painting demonstrations, and live music at casual receptions throughout the tour.

The third of these events in 2012 takes place in downtown Newburyport, Mass., on Saturday Aug. 18, from 3 to 7 p.m., and Sunday, Aug. 19, from 1 to 5 p.m.

The walk includes a reception for featured artist Janice Colby at the Firehouse Center for the Arts in Market Square on Saturday from 4 to 6 p.m.

Colby’s acrylic paintings are reminiscent of a summer day. She captures an exuberant feeling with bright color and a breezy quality with a quickness implied in the brushwork. The exhibition, titled “Delightful,” continues through Sept. 4.

In contrast, the Newburyport Art Association, at 65 Water St., is celebrating the “Absence of Color,” a collaboration between artists Elaine Asplund Russell, Skip Montello, and Michael Wharff, all working in black and white.

This show allows for an experience of natural beauty beyond color. The artists focus instead on the essence of their subjects. Without color-infused emotion or meaning, the simplicity of the spectrum makes it more challenging to define each piece.

“Texture and density interact with light to create degrees of neutrality and form to draw the viewer closer,” Wharff says in his artist statement.

Indigo Artist Studio, at 53 Middle St., will introduce new work by studio artists on Saturday while presenting live jazz music from local band the Chuck Walker Trio and a wine and cheese reception. On display this month are Vermont landscapes by Lillian Coolidge and “Trees,” a series of monotypes by Mary Arthur Pollak.

“We don’t always have regular hours as we are a working studio, so the ArtWalk is a great way to let the public get to know us and our work,” Pollack said.

She said the artists enjoy educating people about their process and techniques, and usually have work in progress so they can demonstrate. 

The Walsingham Gallery, at 47 Merrimac St., will present a free painting demonstration by artist Jim Karlovich on Saturday from 3 to 7 p.m. Known for his masterful wave paintings, Karlovich returns to the series often because each painting conveys a personality.

“I become transfixed watching waves emerge, feeling their power, translucence, and the individual character of each one,” he says in his statement.

Also on this weekend, Valerie’s Gallery is holding a reception with light refreshments for well-known local painter Colleen Kidder, who uses broad brushstrokes and an impressionistic style to evoke different moods in her land and seascapes. It’s at 26 State St.

Three dimensional works are at Somerby’s Landing Sculpture Park, at the west end of the Newburyport boardwalk on the Merrimack River. The exhibit of contemporary sculptures by New England artists includes recently installed works by Gillian Christy, Peter DeCamp Haines and Joseph Wheelwright, joining those by Wendy Klemperer, Robert Motes and Dale Rogers. This marks the ninth year of outdoor sculptural exhibits at the historic waterfront.

The Bridge Gallery will be hosting a different kind of art exhibit. R. “Early” Hollandsworth, a flute maker and player from Merrimac, Mass., is showing six of his American-grown bamboo flutes, each designed in a particular key. Hollandsworth will perform on his instruments during the opening reception on Saturday from 5 to 7 p.m.

The Bridge Gallery is also hosting “Everything Newburyport,” featuring six exhibitors with paintings of scenes in and around the city.  

In all, 17 galleries participate in the ArtWalk events. The others include The Churchill Gallery, Connor Summers Gallery, Spirit of Newburyport Studio, Chameleon, Alan Bull Studio, Lepore Fine Art, MPG Home Design, Nantucket Stock Exchange Too, Sisters We Three, and Sweethaven Studio & Gallery.

The next and last ArtWalk of the year takes place on Oct. 20 and 21. Maps are available at any participating gallery or at the Newburyport Chamber of Commerce.