Hi,
What you are describing there is definitely not Kalsomine, which has a very powdery film, easily removed with water, see:
http://www.apmf.asn.au/html/document_pages_37.html
The other factor against it being Kalsomine is that it was applied with a roller, Kalsomine was popular in the 50s and roller were not used that much then, Kalsomine was usually applied with a broad brush.
Have you tried a heat gun?