<I doubt very much if most CRTs are at all light-sensitive.
You kidding? Those phosphors are quite sensitive to light at the right
wavelength.
Everyone forgets a plumbicon (and predecessors) used a phosphor coated
target that the image impinged on and then was scanned with a electron
beam with the incident current sensed using an internal collector grid.
Maybe you had to work with the old mono camaras with a tube in it rather
than a CCD.
Allison