Károly Ferenczy was the style and school-founding master of Hungarian painting. It is his merit, that Nagybánya became a notion of style and was able to change the nature of Hungarian painting. At the beginning he was attracted by subtle naturalism as well. Following his three years' stay in Paris, his pictures were characterized by mother-of -pearl nuance, light colours, refined drawing, descriptive rendering and a consciously chosen lack of composition: Girls Attending to Flowers, Boys Throwing Pebbles into the River.
In spite of the fact that his formal language had strong bonds with the tendencies of naturalism, he was not interested in taking a social stand at all. In contrast with the circle of Hollósy, he felt that it would be anachronistic to have the founding of national art as a goal. In contrast, he is the first Hungarian painter to reach the self-standing visuality, the principle of the value of the independence of self-defined painterly reality, the principle of l'art pour l'art.
His first independent period began with the founding of the Nagybánya art school in 1896. At the beginning, Ferenczy participated as well in the illustration of the poems of József Kiss: Daphnis and Chloe. His illustrations still reflect a certain secessionist handling of the line and a decorative thrust: Souvenir of Naples.
Nevertheless, the secession was only an interval for him. His religious experience of nature and lyrical sensibility inspired huge compositions under the influence of his experiences at Nagybánya. This experience was deeper and more complicated to be rendered with a simple natural motif or the cutting out of the view. This is why the otherwise atheist Ferenczy chose biblical themes. These had lost their historical approach and became the instruments that rendered the experience of nature of the artist. Sermon on the Mount begins the row of the paintings with the new style. It was followed by several visionary scenes, which were dominated by deep tones, colours appearing among green nuances: The Three Magi, Joseph sold into Slavery by his Brothers, Isaac's sacrifice. The experience was evoked by nature, but the simple view was transcribed into a vision by Ferenczy and this way he exceeded the describing naturalism. The inner emotional world and the view are bound together on these pictures.
The most significant feature of his human and artistical character was his consciousness; the conscious analyzing of the matters that appeared. In the first years at N, a lyrical formal language rendered his pantheistic experience of nature. The lyrical experience couldn't be increased anymore and the intuitive astonishment had to be followed by scientifically based cognition. Ferenczy, who was more cultivated in artistical matters than his colleagues, had to face the problems of plein-air consciously. While trying to render the free air artistically, he reached a material, synthesizing impressionism.
He was interested in the matters of tones of the impressionism in the second phase of his Nagybánya period, between1903 and 1906. The paintings made in this period are dominated by the vibration of the disintegrated, scattered light: Summer, Winter. The way he understood nature became more objective and was more strongly concentrated on formal matters. His aim was something more then the simple rendering of the view; he tried to compose the view, to change it in an aesthetical way instead. He drafted his aim as "colorist naturalism on synthetic basis" in the catalogue of the 1903 exhibition. He analyzed the relationship of spots that were reduced to the plain in fact and only were referring to space and body. He researched the possibility of the contrast and harmony between the spots. His style could be characterized with excess in the use of colours and a closed up composition that held together the motif: Woman Painter, Evening in March, , October, Morning Sunshine. The excessively intense spots of colour do not primarily represent the natural motif on these pictures. They become a self-standing plastic value, painterly reality, and the components of an autonomous aesthetical world. The theme of these pictures began to loose its role. The painter reached the principle of clear painting of view and status.
His oeuvre was closed with this in fact. He became a teacher of the Academy of Fine Arts and moved to Budapest in 1905. He spent only the summer in Nagybánya. His last pictures were summarizing: Double Portrait, Archers.