Like the painting itself, the teaching was for Ion Dumitriu a vocation, before being a job. When he felt like an artist and wanted to take the classes of a Plastic Arts Faculty, he studied at the Pedagogic Institute. After that, he taught drawing for many years in elementary schools. Later on, when he completed his studies at the “Nicolae Grigorescu” Plastic Arts Institute (“no mandatory attendance”), he chose the section “Museums. Drawing Teacher.” He worked with the students of “Nicolae Tonitza” high school for almost two decades, but also at the elementary school level (grades V to VIII). When, after 1989, he received an offer to become a teacher at the Art Academy (the new name of the former Art Institute), he declined such offer. He lover very much the children and carefully watched their becoming adolescents. The education of an artist was for him not only a professional formation process, but general-human, essentially moral. He taught his students not only to draw or to paint, but also to think, to understand what happens with them, to distinguish the good from the bad, to appreciate the true feelings as well as the good values of life. Briefly – as it is said in a too pathetic formula, but perfectly true in his case –, he taught them to be human beings.
He was a part of the rare “species” of teachers who were really interested by the genuine creativity of the children. He saw in their fantasies, in their way of feeling the surrounding reality, paths towards the authentic and profound artistic beauty, and not only of the world. He organized in 1979 a big exhibition at the Bucharest Collections Museum with the drawings of his students. With that occasion, he met Radu Petrescu, another grand Romanian explorer of infant creativity. In the diary of the teaching years of Radu Petrescu (1951 – 1954), published in the Back Small Telescope (1977), there are many pages analyzing the texts written by his students, and in Berenice’s Hair (1981), that covers the beginning of the next decade (1961 – 1964), detailed attention was paid to the drawings made by his own children. In the same book, upon the preparation of the diary for publication, Radu Petrescu included a detailed comment (dated 1979) upon the drawings made by Ion Dumitriu’s students.