Dark vertical stripes between color bars?

[Phil Nelson]

Here's something I hadn't been curious about until I viewed things on an oscilloscope: dark vertical stripes between bands in NTSC color bars.



In this scope pic, the lower trace shows the video output from my pattern generator. The top trace shows the messy signal at the input of my 1st video amplifier tube. Presumably the dark stripes are those "stalacites" dripping down between color bands, arising somewhere in the front end.



I hooked up a 1980s Panasonic and saw that it has stripes, too, although not so pronounced.



I'm not going to lose sleep over the stripes if they can occur in an OK-looking 1984 TV. Just curious about what causes them.

Phil Nelson