[hdgvhicv]

Yes the high frequency noise. Depends on how good the hf filter is.

[chadgpt3]

Why would you have one? Want the image to look blurrier on purpose? Color TVs have one to block the color dots.

[Majromax]

If you're deliberately displaying the image in black and white, the colour pattern is interference that should be suppressed.

However, this practice was not universal, and archivists have now recreated colour copies (https://en.wikipedia.org/wiki/Colour_recovery) of some shows where only black and white recordings survived by reconstructing the colour from these interference signals.

[actionfromafar]

A very late in the signal chain color decoding. :-D

[ErroneousBosh]

There's no real luminance content above about 5MHz, and TVs used to notch out the colour at 4.43MHz.

As an aside, you can do all this digitally now with phenomenally sharp results.