SAM’s fine collection of Alden Mason’s paintings currently on view spans several decades. Hanging on all four walls of a third-floor exhibition gallery, they surround the viewer and yield an unexpectedly unified impression.

This is odd, since Mason has employed very different media, and for years has experimented with distinctly different "styles" in producing his work. Some of the pieces have a liquid watercolor feel, others a constructed sense where every mark bears witness to the artist’s hand. There are small, delicate pieces framed under glass, and large, robust, expansive paintings. There is figurative work and abstract painting. Yet despite all these variations the pieces very much come across as landscapes.

The exhibition begins with the 1947 piece, "Darrington Rain," a lovely watercolor that was bought by the museum the year it was painted and holds clues and promise for the entire exhibition.

The wall text states that this painting depicts the countryside in Darrington outside Seattle, where Mason grew up. Yet the real subject of the piece is neither land nor family home, but the sky, a vast horizon full of ominous galumphing storm clouds. These take up at least three-fourths of the painting, floating across the paper in a wet and strongly patterned dance. We see a tiny barn and silo, but they are almost completely engulfed by cloud. In the foreground the artist has given us the rhythmic march of fence uprights in the same Payne’s grey of the clouds.

We are considering a landscape, which is really a skyscape, and actually an inspired painting of imagined pattern. If the most literal piece in the group of paintings is barely a landscape, how then could the rest be called landscapes when few even purport to be?

The answer lies in Mason’s treatment of the painting surface itself. He has consistently taken on the place of the painting — its "real estate" — as the actual subject of his work. Whatever they’re called, each painting is about the painting itself: the landscape within the confines of the four edges of the piece.

And like "Darrington Rain," all the paintings on view are strongly influenced by rhythmic interplay. This emphasis on pattern, as it has throughout the history of the decorative arts in many diverse cultures, flattens out the visual field. We don’t get a sense of depth, foreground, or background, but rather a continuous wash of color and shape. The only spatial clue we get in "Darrington Rain" comes in glimpses of white paper left empty between those huge voluminous clouds.

But isn’t landscape all about foreground and background? Isn’t that how we know we are seeing a landscape — because it gives us a window into the distance somewhere?

Yes. And no: landscape paintings have always been about place, about depicting how a place appears to the artist, but much of what we take to be landscape painting is actually tradition-based, rather than rooted in some inherent truth about the way we see where we are.

Watercolors have long been associated with the British landscape tradition, and William Payne, the creator of the eponymous grey, is instructive in this regard. He was an 18th-century English watercolorist who painted slate quarries. Needing a color to bring out the subtleties in the slate, not just its darkness, he put together indigo (a color with antecedents in a very different landscape, grown in and imported from India), raw sienna (obtained from clay from the landscape around Siena, Italy), and a lake, a pigment made from the action of dye on a chemical base.

An engineer, Payne knew his way around materials. He was also innovative as a landscape painter and moved the watercolor tradition toward poetics. Doing away with first outlining forms in pen, which had long been the norm, Payne wetted the paper first and as a result got more suggestive, freewheeling shapes; we see exactly that operation employed in Mason’s 1947 watercolor.

Mason has worked with many techniques in his long career, and like Payne, is obviously good with technicalities and materials. The paintings on view at the SAM exhibition, like all paintings, are end products of the act of painting. And like the white space between the clouds in "Darrington Rain" the paintings reveal the relationships of the elements he’s juggled in producing it.

These are landscape views: depictions of places where he has been in his mind, mental places if you will, while painting away in his studio. If we imagine the 18th-century watercolorist painting in plein air and recording what he sees, we can just as well imagine Mason at work in his studio/laboratory, his paintings reporting back what transpired there.

Rather than depicting space, more often his paintings seem to tell us about time, and about the speed with which the paintings came together. Mason got national notice for his series of 1970’s stained oil paintings like "Inside Outside Landscape." Though oil-based, the look is decidedly large-scale watercolor.

Watercolor is the purest form of artist paint, being mainly pigment, suspended in distilled water with a touch of binder to hold water and color together and another touch of preservative and solvent to keep it glowing long after it has dried. The purity of watercolor makes it fragile — the usual substrate is paper, also fragile — and so most watercolors on paper are small, paper-sized, and always framed behind glass or plexiglass.

In the 1970’s American painting was getting bigger and bolder, and delicate watercolors hiding behind glass weren’t going to do the trick. Several artists began experimenting with abstractions that could allow them to mimic watercolor by liquefying oil paint, a medium that could happily sit on a canvas, stretched or not, without protection.

This allowed for more physically dynamic work, and without the restrictions of glass size or the considerable expense of plexi, paintings could be as large as the artist wanted. Using liquefied oil also meant that paintings could be completed quickly. This in turn meshed nicely with the philosophical strain of the era — being here now, and all that.

Using the thinned oil, Mason achieved a fluid film across the painting surface. Indeed, the landscape is both inside and outside — it's literally all one — and the transparency connects idea and technique: what you see is what he did. By getting at the watercolor look, pieces like "Inside Outside Landscape" brought along the historic connection of watercolor to landscape, even while turning it on its head. Really the only connection to traditional landscape and the landscape of the Pacific Northwest, where Mason has always been based, is the inclusion of green, a color that shows up in every painting in the SAM show.

The oil paint used in this piece and in others from the series had to be thinned with copious quantities of solvent to keep the paint liquid and pourable. The paint thinner off-gassed as it dried, which in the moist Northwest would take a while. Three decades ago the fumes from the available solvents could and did cause very serious health risks. Used without a great deal of ventilation, the fumes could actually kill. Mason got very ill, almost succumbing to these serious dangers; fortunately for him, us, and art history, he survived and switched to acrylics.