[3] In 1960, Jäger accepted a position as a technical teacher of photography at the Werkkunstschule Bielefeld and established the medium as a basic discipline there.
In 1972, this led to the founding of Photo/Film Design as a specialisation at the University of Applied Sciences Bielefeld, with contemporary photography and media studies.
On the occasion of his retirement, the institution praised Jäger's decisive contribution to photography being "given equal status with the arts of painting and sculpture.
Jäger was for eight years Dean of the Faculty of Design and from 1993 to 1997 Vice President for research and development tasks of the FH Bielefeld.
The text was brought to his attention in the mid-60s by Hein Gravenhorst, a friend and fellow artist in generative photography, whom he had met through Manfred Kage.
It allows a methodical creation of aesthetic states by dissecting the creation into a finite number of specifiable and describable single steps.Thus works of Generative Photography are a rational, apparatus-driven art confluent with the emerging computer age that follow a programmed design that applies mathematical and numerical parameters to artistic projects, and which equally entails development of 'concrete' artistic approaches.
Jäger defined the Generative Photography process as one of "finding a new world inside the camera and trying to bring it out with a methodical, analytical system.
[13][14] In his camera photographs of natural and technical objects from 1971 to 1991, Jäger consistently pursues the serial principle of logical sequences.
In his group of luminogram works Colour Systems of the early 1980s, photographic paper no longer appears as a picture carrier but as an object of the artistic process.
Both groups of works are inspired and derived from the optical program of the pinhole structures, but they modify it through digitization and lead to their own forms.