Film historian, documentary filmmaker, and technician. Co-founder of film archive which is now part of Slovak Film Institute founded in 1963. His main domain was early photography and cinema in Austria-Hungary and Slovakia. He made around 400 documentary films about technicians, inventors, artists, as well as about history of Slovak cinema, and particularly 20-part television series Dejiny malej mechanizovanej múzy which he talked about as film version of his book Kapitolky z dejín nemého filmu na Slovensku. Rumanovský also traced lost copy of film Jánošík from 1921, and directed its reconstructed version with sound, premiered in 1975. He was president of Spolok priateľov staroslávneho Devína, and organised Eduard Schreiber Film Festival in Lednické Rovne.
- Books by Rumanovský
- Kapitolky z dejín nemého filmu na Slovensku. (Slovak)
- Jozef Petzval: Život a dielo, Martin: Osveta, 1957. (Slovak)
- Jozef Petzval, priekopník fotografickej optiky, Bratislava: Čs. štátny film, 1960. (Slovak)
- Articles on Rumanovský
- "Ivan Rumanovský", Film.sk 5, 2009. (Slovak)