Symbolism with a combination of geometry, figuration, scientific research and religious practices.
Her symbolic visual language has an ordered progression that reflects her understanding of grids, circles, spirals and petal-like forms.
Spiral forms appear often in her art. Spiral suggests growth, progress and evolution, color choices also are metaphorical in nature.
At the age of 44, af Klint painted her first series of abstract paintings. Svanen (The Swan), No. 17, Group 9, Series SUW, October 1914 – March 1915, a work never exhibited during af Klint's lifetime.
The works for the Temple were created between 1906 and 1915, carried out in two phases with an interruption between 1908 and 1912. As af Klint discovered her new form of visual expression, she developed a new artistic language. Her painting became more autonomous and more intentional. The spiritual would continue to be the main source of creativity throughout the rest of her life. The collection for the Temple is 193 paintings, grouped within several sub-series. The major paintings, dated 1907, are extremely large: each painting measures approximately 240 x 320 cm. This series, called The Ten Largest, describes the different phases of life, from early childhood to old age. Quite apart from their diagrammatic purpose the paintings have a freshness and a modern aesthetic of tentative line and hastily captured image: a segmented circle, a helix bisected and divided into a spectrum of lightly painted colours. The artistic world of Hilma af Klint is impregnated with symbols, letters, and words. The paintings often depict symmetrical dualities, or reciprocities: up and down, in and out, earthly and esoteric, male and female, good and evil. The colour choice throughout is metaphorical: blue stands for the female spirit, yellow for the male one, and pink / red for physical / spiritual love. The Swan and the Dove, names of two series of the Paintings for the Temple, are also symbolic, representing respectively transcendence and love. Understood as gates to other dimensions, her paintings call for interpretation on a narrative, esoteric and artistic level while evoking primordial geometry and humanistic motifs. When Hilma af Klint had completed the works for the Temple, the spiritual guidance ended. However, she continued to pursue abstract painting, now independent from any external influence. The paintings for the Temple were mostly oil paintings, but she now also used watercolours. Her later paintings are significantly smaller in size. She painted among others a series depicting the stand-points of different religions at various stages in history, as well as representations of the duality between the physical being and its equivalence on an esoteric level. As Hilma af Klint pursued her artistic and esoteric research, it is possible to perceive a certain inspiration from the artistic theories developed by the Anthroposophical Society from 1920 onward.
Through her life, Hilma af Klint would seek to understand the mysteries that she had come in contact with through her work. She produced more than 150 notebooks with her thoughts and studies.
Klint met Rudolf Steiner for the first time. In one of the few remaining letters, she asked Steiner to visit her in Stockholm and see the finished part of the Paintings for the Temple series, 111 paintings in total. Steiner did see the paintings but mostly left unimpressed, stating that her way of working was inappropriate for a theosophist. According to H.P. Blavatsky, mediumship was a faulty practice, leading its adepts on the wrong path of occultism and black magic. However, during their meeting, Steiner stated that af Klint's contemporaries would not be able to accept and understand their paintings, and it would take another 50 years to decipher them. Of all the paintings shown to him, Steiner paid special attention only to the Primordial Chaos Group, noting them as "the best symbolically". After meeting Steiner, af Klint was devastated by his response and, apparently, stopped painting for 4 years. Steiner kept photographs of some of af Klint's artworks, some of them even hand-coloured. Later the same year he met Wassily Kandinsky, who had not yet come to abstract painting. Some art historians assume that Kandinsky could have seen the photographs and perhaps was influenced by them while developing his own abstract path. Later in her life, af Klint made a decision to destroy all her correspondence. She left a collection of more than 1200 paintings and 125 diaries to her nephew, Erik af Klint. Among her last paintings made in 1930s, there are two watercolours predicting the events of World War II, titled The Blitz and The Fight in the Mediterranean.
Despite the popular belief that Hilma af Klint had chosen to never exhibit her abstract works during her lifetime, in recent years art historians such as Julia Voss have uncovered evidence that af Klint did attempt to show her work. Around 1920 in Dornach, Switzerland, af Klint met Dutch eurythmist Peggy Kloppers-Moltzer, who was also a member of The Anthroposophical Society. Later, the artist travelled to Amsterdam, where she and Kloppers discussed a possible exhibition with the editors of art and architecture magazine Wendingen. Although the Amsterdam talks were not successful, at least one exhibition of af Klint's abstract works took place in London several years later, in 1928 at the World Conference on Spiritual Science in London, for which Kloppers was a member of the organizing committee. Originally, af Klint was excluded, but after Kloppers' insistence, she was added in the list of participants.
She sailed from Stockholm to London, along with some of her large-scale paintings. In her postcard to Anna Cassel (discovered only in 2018) af Klint wrote that she was not alone during this 4-day trip. Despite af Klint not having named her traveling commpanion, Julia Voss suggests that it was most likely Thomasine Andersson, an old friend from De Fem days. Voss also suggests that it is probable that the works were from the Paintings for the Temple series.
Hilma af Klint died at 81 in Djursholm, Sweden, after a traffic accident. She had exhibited her work only a handful of times, for the most part at spiritual conferences and gatherings. She is buried at Galärvarvskyrkogården in Stockholm.