All the equipment I've ever acquired with a P-7 CRT in it has employed
a orange optical filter, sometimes solid tinted plexyglass, sometimes a
cinemoid gell. This includes a number of really old marine radar sets
and some vintage hospital diagnostic displays including the exact same
heart monitor that can be seen on the movie "The Right Stuff" while the
would be astronauts are being run through the meat grinder at the
testing clinic.

As an interesting aside, I also had the exact same motorized
positioning chair that appeared in that movie too! Part of my chair, a
heavy gearbox motor and speed controller board ended up as the motion
engine driving the RA tracking (azimuth) feed car on the famous Big Ear
radio telescope of John Kraus at OSU in the 1990's when I was working
with that SETI project.