After being bought by 3M, Ferrania certainly concentrated on amateur film. Others might be able to fill in more gaps but I do not believe that they produced film specifically aimed at professionals. Their C41 film was good, but a little more grainy than Kodak and Fuji, especially the 400 and 800 ASA/ISO films. But they were probably not pumping R&D funds into making the best possible film, they were making film aimed at the mass market who wanted 6x4 prints and rarely anything else. I never used their slide film but I get the impression it was not highly thought of?
Looking back at the film I shot under the Prinz-Color brand in the 70s and 80s, and the Truprint brand in the 90s which was all Ferrania manufactured film....and the Ferrania Solaris I shot in the early 2000s....it's good stuff in 100 and 200ISO, pretty much on a par with the better known names. I was shooting it because it was effectively free. As I said, I grew up near PTP which was possibly the biggest film processing lab in the UK. But it was also open to the public who could drop off film there and pick up the prints and negs the following day....along with a free "Prinz Color" film, initially 100ASA later 200ASA.
I don't think we should underestimate just how much film Ferrania was cranking out in those days. They were supplying a lot of those huge labs across Europe and certainly for a time they were supplying Wal-Mart in the USA too. Goodness knows who else....I mean, do we know who made Kirkland film for Costco?
Of course the main Ferrania campus is no more and all that remains is the LRF (the research building, much smaller). But the documents from those days seem to have been kept along with some of the know-how. It's far from a turnkey thing to resume colour film production but they have a bit of an advantage over Harman in some respects, in that they've actually done it before.
