Basically I'm wondering what the maximum theoretical resolution is that can be recorded to film using this machine.
There is no resolution defined by dedicated pixels as picture generation (the tube) as well as picture storage (the film) is analogue. Any description in terms of modern digital imaging will miss the capabilities.
Quantisation in vertical is ...
I've never used one of these devices, but I can see from the photo that the device has the typical inputs you'd find on studio equipment at the time, and for many years after.
It appears to accept NTSC composite video, TTL RGB, and Analog RGB with a composite sync, or RGBS (using EXT. SYNC input). NTSC composite input would work with consumer VCR's and ...
The Chroma Pro was a series of screens introduced after 1985. I remember using a CM 2000 in the late 80s.
RGBI is essentially IBM CGA.
RGB is Analogue RGB.
I used both modes with IBM and an Atari ST.
XRGB in turn should be what Apple used to call the Apple III's digital video signal. It's a 4 bit TTL compatible digital port. See this pinout). The Extended 80-...
From my reading of that post linked above, XRGB is a variation of RGB that maps to NTSC artifact colors, rather than the usual 16 seen with RGBI. This is likely related to the Apple 2 and IBM CGA 16 color artifact palette and monitor suitability for software written with artifact color in mind.