In this era of re-examining our values in the face of increased social tensions and existential threat, Philip Guston’s sour yet exuberant late paintings promise to tell us who we are and what beliefs we must cling to in order to go on.

Guston, a giant of 20^th Century painting, scandalized the New York art world in 1970 by turning his back on the prevailing trend of pure abstraction. He embarked instead on an inspired journey creating politically-infused, tragic-pop canvases that exploited a wacky cartoon-style imagery. Although these works failed to sell in his lifetime, they changed the dialogue of painting. He stood by his vision, supporting his family by teaching at Boston University, and produced the bulk of his oeuvre in this new style until his death in 1980.

The retrospective “Philip Guston Now” displays 100 works at Boston’s Museum of Fine Arts through September 11. Co-curated by the National Gallery in Washington, Houston’s Museum of Fine Arts and London’s Tate Modern, the exhibition then travels to each museum in turn, swelling to almost double its initial size before ending in early 2024.

Born in 1913, Guston’s style evolved in creative tension with the foremost art movements of his troubled century. His imagery grew out of early personal trauma, his intense response to social and political events, and a deep grounding in the traditions of Western art.

From the start, the curators understood Guston’s work would provoke, even after 42 years, with its images referencing suicide, lynchings, torture and concentration camp victims, as well his notorious appropriation of Ku Klux Klan-style garments.

The Pandemic’s shuttering of museums in 2020 and racial, economic and political polarization around the George Floyd riots convinced the sponsoring museums to delay the opening until, in the words of MFA Director Matthew Teitelbaum, and MFA co-curators Megan Bernard, Ethan Lasser, Kate Nesin and Terence Washington, such time as the “powerful message of social and racial justice that is at the center of Philip Guston’s work” could “be more clearly interpreted.” The order of exhibitions was reconfigured, and the MFA’s version, significantly smaller in terms of scale, moved to the front of the line. Many criticized a proposed four-year delay as a loss, given the need for public responsibility in this fraught time. Guston himself, after all, had not shrunk from a sense of public duty in speaking explicitly in a timely fashion about contemporary social and political issues through his art. Accordingly, the museums, working together through Covid conditions, revamped and expanded the exhibitions and their programming with alacrity, bringing the work to the public only two years after originally scheduled.

Mindful of past complaints of insensitivity toward minority visitors, the MFA curatorial team decided to buffer potentially disturbing imagery, but not to censor it. They stepped up efforts to ensure greater inclusivity and responsiveness to their audiences’ needs. They rewrote texts and asked a trauma specialist to frame a message acknowledging viewers’ potential vulnerability and forewarning them of disturbing content. The curators also structured the order of presentation and commentary to attune visitors along the way to the personal relevancy as well as the social contexts in which Guston’s imagery arose. Timelines mounted in corners of the galleries relate the artist’s personal milestones to political and art-world events. Graphic photographs of historical atrocities are presented in closed cabinets with viewer discretion advised.

A superb scholarly catalog by curators from each museum includes responses from living artists. Wall-texts, audio tours, public panels and interpretive videos have been made available. Off-site (on the MFA’s website), one can view many of these, including Teitelbaum’s conversation with Guston’s daughter, Musa Mayer, whose newly reissued memoir of her parents, “In the Night Studio,” provides a humanizing context for this trove of works.

I visited the exhibition on the Juneteenth holiday and enjoyed the celebratory air of lawn festivities and free admission. Two weeks later, on the July Fourth weekend, a band of white supremacists belonging to the “Patriot Front” marched through Boston in white masks and beat up a Black artist-activist who attempted to videotape their antics. The MFA’s efforts to educate the public about art as a key element in a healthy and democratic civil society provide a welcome contrast to the vision of racists sullying Boston’s Freedom Trail with cowardice, bigotry and violence. Such efforts must be a model for the future, as ever-more-violent attacks on our open culture persist.

In hindsight, it’s plain that Philip Guston’s art was always embedded in the politics and pain of his world. Born in Canada in 1913 to a family of Russian-Jewish immigrants, the young Phillip Goldstein learned early lessons in violence, racism and anti-Semitism. Soon after moving the family from Canada to Los Angeles, his despairing father committed suicide. Guston later claimed it was he who cut down the body. Further tragedy struck when his older brother died after a car accident that crushed his legs. Guston’s own socially-conscious art suffered attack when Los Angeles police raided an exhibition in protest of the trial of the Scottsboro Boys that featured his painting of a Klansman whipping a victim.

The curatorial narrative reveals a progression of stylistic changes and developments, beginning by visually pairing several stylistically distinct works from far-flung decades in the first few rooms. While the viewer would do well to pay attention to dates, this presentation effectively highlights recurring themes and makes evident Guston’s lifelong preoccupation with racism and tyranny.

As a youth, Guston was a precocious draftsman and also loved drawing comics. He absorbed the compositional clarity of Quattrocento masters like Piero della Francesca, Massaccio and Giotto and was fascinated by the surrealism of Picasso and de Chirico. Motifs and compositional structures later to recur show up as early as age twenty-two. In the surrealist-inspired “Nude Philosopher In Space-Time,” 1935, an incandescent bulb ending in a glass nipple hangs on one side of a claustrophobic space split between “female” and “male” elements. On the nearby label, Guston is quoted, recalling that as a young teen he painted in a closet under a bare suspended bulb. Elsewhere, the artist refers to those years as being “in a box,” separated off from people. It’s not coincidental, then, for the painter later to represent himself as a head encased in a hood, peering out at the world.

A pair of small and large paintings suggests a foreboding awareness of racial urban violence. In the swirling “Gladiators” of 1940, a knot of hatted and hooded boys of various skin colors slug it out on a city sidewalk with improvised swords, cudgels and garbage can lids. In a later treatment, the cartoonish “Aegean,” 1978, recaps the melee on a 10-foot canvas as a tangle of hairy outstretched arms and paws of varied hues thrusting at each other with their ashcan shields.

In a more realistic portrait, “Sunday Interior,” 1941, a young Black man sits up at a white table next to an open window, cigarette held to his lips and gazing vigilantly, at the artist. Wearing a white dress shirt and stiff green tie, his dark face merges with the dusky interior; a fresh sliver of cobalt sky behind a furled green window-shade lights up the pink shell on the table before him.

A small 1973 canvas just above contains a perfunctory, comic-strip version of the window shade, also jade-green, whose heavy black pull-ring hangs down dead center. The curators’ visual “joke” points out ominous parallels among the green of the shades, the narrow green tie cinching the man’s neck, and the cords hanging straight down in both paintings, one ending in a pronounced loop. Lest we doubt the artist’s frame of reference, a mural-size photo on the adjacent wall displays a collaborative fresco executed by Guston and friends in 1932 in Morelia, Mexico that bursts with images from the history of terror, tyranny and torture, including a murderous Klansman.

In the postwar years, Guston’s struggle with depression and the horrors of World War II corresponded with his turn toward abstraction. “The Tormentors,” 1947, and “Red Painting,” 1950, teem with dark, vibrant, unreadable shapes — suppressed images of conflict and destruction rendered in scarlet, dark reds, deep chestnut, blacks and gold. Yet, although the bleakness and violence of his semi-abstract visions struck a dead end, leaving him exhausted, somehow, he pushed through to the other side. On a trip to Italy, Guston began to create more fully abstract ink drawings. He soon committed to moving to New York and began painting and exhibiting among the Abstract Expressionists.

With this turn, interesting changes begin to happen. He determines to approach the act of painting more spontaneously, adopting the process of continuous painting, wet on wet. His brush strokes, often separate, leaving space between and around them, appear to project color independent of any subject, guided by gravity and the grid implicit in the rectangle of the canvas. He also shifts to markedly lighter values.

The show appears to skip quickly over Guston’s early foray into Abstract Expressionism, without commenting on the discoveries of Guston’s balanced, light-filled canvases of the early 1950s, to get to its paramount theme, his emergence as the father of a new figuration in the 1970s. My own attention lingers, nevertheless, on the smaller questions along the way that perplex the artist, causing frustrations and detours, yet inspiring him toward new experiments with tools, materials and methods.

In this context, a statement Guston uttered in 1973 stands out: “I don’t understand blue.” He calls blue “difficult,” as opposed to the colors he liked — “certain kinds of red and pink and grey and blacks and ochres.” “Some day I’m going to go back into blue,” he promises. “It’s a different state.” Guston continued to chew on this bone.

Blue had hardly been absent from the artist’s early palette. A deadening Prussian blue in “Nude Philosopher” forces the night sky to recede into space. The green-blue miasma of “If This Be Not I,” 1945, casts melancholy over the garments, surroundings and skin tones of children in somber play on a city sidewalk. The dialogue between blue sky and pink shell in “Sunday Interior” seems to presage the frequent counterpoint of red and blue tints in the abstractions of the early 1950s and certainly that in the cartoon-like “Open Window” of 1969, where another blue sky pulls back, this time from the pink plane of a studio wall.

The exhibition narrative dwells on the latter 1950s, when his tender marks begin to turn disorderly and fierce. Previous arrays of fragmented light regroup into brooding coagulations of slathered pigments, as though the canvas itself struggles to contain some inner geography of memories, feelings and questions. The curators point to a clustering of vestigial presences that might foreshadow human figures.

Guston’s dissatisfaction centered on late 1950s works like “Native’s Return,” 1957, “Fable,” 1956-57, and “Painter,” 1959, in which small scumbled areas of middle-value blues — ultramarine, cobalt and Prussian blue, turn darker and greyer, while bright permanent greens become absorbed by cooler viridian and dark green mixes. The ensuing “Cup,” 1972, in which giant murky blue and grey forms begin to cohere among the larger, wilder strokes, leads to series of “Painters” and “Heads” through 1963-65.

As the new decade breaks, the remaining color fades out of most of his paintings, leaving ashen, congealed forms that allude to smoke, studio flotsam and glowering presences. While Guston’s darkening blues hastened his movement toward more defined form, the path to grey and black corresponded to another dead end. What finally emerged to unify Guston’s inner landscape was its polar opposite, a virtually monochromatic range of cadmium reds in all their tints, shades and muddy mixtures, in essence a lighter, more benign cousin of the vicious reds that had defined the works of the late 1940s. For Guston to find a viable path to blue, it would have to manifest not as a route to darkness, but as a component of light.

Things then changed quickly during an extended transition marked by distressing political and personal turbulence. In 1967, Guston briefly left his wife of 30 years, the poet and painter Musa McKim, only to return months later. He draws pages and pages of minimal lines and marks in thick black ink on paper. The following year brings forth scores of small, brash paintings, each one a comic-strip frame dedicated to a single object. These beget the complex larger works of the late 1960s, excoriated then and celebrated now, the “hood” paintings and their companions, which mediate ambiguously between his sense of inner and outer evil.

After his dismal exhibition in 1970, at Marlborough Gallery, where nothing sold, he left the “hoods” and Klan associations to enter a more autobiographical form of symbolic narrative. Personal trauma merges with Holocaust imagery. We see vast piles of bent legs with knobby knees, hobnailed boots and boot-soles, severed feet and genitals. Bare light bulbs hang in confined spaces, tabletops become ocean vistas, and darkened pits swallow human forms and light. Guston’s new painterly self incessantly observes and gathers forms. It’s no longer a head hidden under a hood but a Cyclopean bean that is all eye, open to the world and conscious of inner and outer pain. In 1975, another head comes into play, that of his wife, Musa. He invokes her nurturing sun-like presence with forehead, hair and eyes hovering just over the horizon, the table or the bedclothes.

As his range of imagery grows in the 1970s, Guston seeks more intense, expressive alternatives beyond his cadmium red-based color scheme. In many despairing paintings, there remains the risk of being swallowed up by the dark red-and-black palette of the 1940s. But he seems to call up other lessons learned during his dalliance with abstraction. Perhaps the gore and glory of Guston’s later paintings owes the most to his mastery of a faster, fresher technique of agitating pigment directly on the canvas in his search for light. In exchange for the freedom to work at top speed, slopping wet paint on wet paint, the painter must give up control of a precisely ordained composition. He must keep the new image always in play, its truest form only arising through the bodily energy of the brushstrokes in the moment of becoming.

Since Guston’s early lessons from Piero and the oppressive color schemes of the late 1940s that left no emotional opening, significant changes in his use of color had come about. No longer locked in the caverns — or closets — of deep reds, greys and blacks, his lighter palette of the 1950s and ‘60s opened up a wider range of options and experimentation with light and color.

The lighter tints of Guston’s brush strokes in the early 1950s were more permeable and distinguishable. Lifting colors together on the brush and depositing them un-mixed on the canvas, he could trigger a dance of complementary and near-complementary warm reds and cool blues, charming the eye in the moment of perception. In his large abstract canvases, Guston learned to conserve areas of neutrals — beige, white and grey — especially toward the outer edges, which tended to isolate and magnify the kick of areas of more intense color.

Capitalizing on the optical law that grey next to a bright hue generates the perception of its complement, he also took advantage of the corollary, that a tiny quantity of a cool or red hue added to neutral grey can subliminally transform the tone and mood of the painting without producing a clear perception of that hue. Often in his late figurative paintings, where cadmium reds, pinks and darks do the heavy lifting, Guston cranks up the proportion of blue in his grey ground to the precise strength where a sense of that hue breaks across threshold of perception and creates a preternatural luminosity.

Pushing blue to its maximum strength seems to be a late achievement for Guston. In Western cultures, blue is known to carry soft, spiritual, feminine and even maternal overtones — as Guston also understood from his Madonna-like painting of 1930, “Mother and Child.” It may not be too far-fetched to see, in Guston’s failure to “understand” blue, anxieties about dependency and feminine power, as well, perhaps, as a wish to subject these forces to rational, or possibly masculine, control­.

The poignant charge injected by blue in Guston’s paintings toward the end may come from finally relaxing his guard, allowing his concerns about femininity, intimacy, the infinite, and the oceanic to surface. Certainly, in his canvases from 1975 onward, when his wife Musa belatedly entered into his imagery, intimations of mortality were at hand.

The fickle emotional state of many of the giant paintings of those last years seems to correlate to the turbulence and intensity of the surrounding space or sky. His color environments become more uneven and edgy, ranging from oppressive blacks, debilitating greys and encumbered pinks to rare, escalating hints of embattled blue. In “Wharf,” 1976, blue’s role is subtle. A compressed swath of dim blue-grey above appears to lift the central image while repulsing the spreading clouds of late sunset. From below, black waters flecked a menacing green and orange rise toward the Wharf, a reddish structure comprised of buildings, body parts, and an artist’s easel. In the middle ground, rusty vapors mingle with dusky blue in an unstable expanse of sky above two heads still afloat. The painter, holding head and brush aloft, races to finish the features of his wife’s dimming face, already half submerged with his under the advancing tide.

In “The Ladder,” 1978, a saturated sizzling electric blue denoting either the sea or a wall bisects the worlds of man and woman. The painter, all legs, scales a ladder precariously balanced on a thick line, in an effort to reach toward the half-disc on the horizon that is his wife’s partially-obscured face (her poetry at this point has been silenced by a stroke). The blue plane that potentially connects the couple whether read as vertical or horizontal, is forced by the laws of optics to push away from its complementary­­ — a ropy curve of cadmium orange slapped with white.

Weighing in like a pyramid at the entrance to the Boston exhibition, the “Couple in Bed,” 1977, could also close as a final, triumphant image transforming blue into an agent of healing. Sheathed in the blue-black shades of night, husband and wife lie enfolded by a pale-blue-and pink comforter, bound to each other by runnels of plangent ultramarine glazing. Their bodies are foreshortened like Mantegna’s “Lamentation of Christ.” The man’s knees are drawn up and his studded shoe-soles face outward. The round blank face of his wristwatch, perfectly centered, encompasses all the time in the world. Pulling his wife close, the painter clutches three long brushes whose bristles, stained with the colors of the canvas, also echo the hues of the painter’s dreams: black, red — and blue.

(“Philip Guston Now” remains on view through September 11 at the Museum of Fine Arts, 465 Huntington Ave., Boston, Massachusetts, before traveling to The Museum of Fine Arts, Houston (October 23-January 16, 2023), The National Gallery of Art, Washington, D.C. (February 26-August 27, 2023) and the Tate Modern, London (October 5, 2023-February 25, 2024). For more details on tickets to the Boston showing, visit https://www.mfa.org/exhibition/philip-guston-now.)