Along with a love for the art of Whistler, Pankiewicz developed an interest for Japanese aesthetics. This interest became stronger through his close relationship with Feliks Manggha-Jasienski, an exceptional art collector and connoisseur who propagated his collection of Japanese woodcuts among Polish artists Jasienski przy fortepianie (Jasienski at the Grand Piano), 1908). Pankiewicz's paintings reflect Japanese principals of compositional asymmetry and often include various Oriental items, including kimonos, porcelain objects, and drawings Japonka (Japanese Woman), 1908; Wazon perski (Persian Vase), 1908; Martwa natura z blekitnym wazonem (Still Life with Blue Vase), c. 1900; Budda i lewkonie (Buddha and Stock Flowers), 1906.
During numerous trips to Italy and France during the first decade of the 20th century, the artist produced a series of watercolor sketches of landscapes that were condensed, ethereal, luminous, and intense in color. These were a harbinger of subsequent stylistic phases that were marked by a fascination for the art of Pierre Bonnard and Paul Cézanne. Bonnard and Pankiewicz were friends and during summer vacation in 1909-1910, they shared a studio in St. Tropez. In 1911-1912 they traveled and worked together, painting in the open in Normandy, at Giverny, and Vernon. It was Bonnard's influence that prompted Pankiewicz to expand his palette and introduce a Fauvist system of colors that were strong, saturated, and juxtaposed in a contrasting manner Kobieta czeszaca sie (Woman Combing her Hair), 1911; he assigned paramount importance to the color composition of his canvasses Port w Concarneau (The Port at Concarneau), 1908). Intense sensitivity for the pictorial qualities of the plane and analysis of the relationships between color tones co-existed in his paintings with a compositional discipline that the artist drew from the works of Cézanne. Cézanne's aesthetic became an even stronger influence during Pankiewicz's stay in Spain, where he enjoyed close contacts with Robert Delaunay, with whom he shared a studio in Madrid. In his landscapes dating from between 1914 and 1919, natural forms and buildings are clearly geometric in form; at the same time, the structure of these compositions is highlighted while the palette is dominated by clear colors illuminated with strong, southern sunlight Ulica w Madrycie (A Street in Madrid), 1916; Taras w Madrycie (A Terrace in Madrid), 1917.
Another change in his formula for painting came in the 1920s, a decade during which he was additionally very active as a teacher. Around this time, Pankiewicz abandoned his post-Cubist interests in favor of a traditionalist aesthetic that referenced earlier art and was based on direct observation of nature. The galleries of the Louvre became the inspiration for both Pankiewicz and his students. The artist reverted to traditional painting skills, modeling his forms from light and shadow; he also studied gradations of color, building his shapes softly, using smoothly laid patches of color. His spacious landscapes from Sanary, Cassis, and La Ciôtat frequently depict trees in the forefront, hills covered in pine trees, and glimpses of the sea in the distance. These canvasses were highly suggestive in their representation of spatial depth. At the same time, Pankiewicz limited himself to tones of olive green, warm browns, and cool blues that passed into pinks Pejzaz poludniowy z domem (Southern Landscape with a House), c. 1925; Pejzaz z Cassis (Cassis Landscape), 1928. Pankiewicz also produced decorative still lifes, their primary motif being an abundant bouquet of anemones in a vase. His still lifes from the 1930s are characterized by both decorative arrangements and by mimetic recreation of different textures - the matte surface of porcelain, the glow of a faience vase, the transparency of glass, reflections gliding over the rounded surfaces of fruit, the softness of patterned fabrics Martwa natura z zielonym dzbanem (Still Life with Green Pitcher), 1929. Pankiewicz began to analyze the skills of 17th century Dutch masters; his narrow color scheme, dominated by browns and greens, served to create a mood of calmness and reflection. In 1929 the artist was invited to participate in decorating Wawel Royal Castle in Krakow, a project that was directed by Adolf Szyszko-Bohusz. He continued to live in Paris, and in 1930-1931 executed eight oil panels for the Royal Chapel, including the plafond paintings Nawiedzenie (The Annunciation) and Ucieczka do Egiptu (Escape into Egypt).