Shimmering green pixels on R-Pi 3

RISC OS 5.28 running on a Raspberry Pi 3. If I display green pixels of values #4A9067 .. #4E9067 I get a shimmering pattern showing on the screen. It’s a pattern of single pixel noise appearing on the display, not the scren buffer – your typical sort of values dancing in a register effect.

Some sort of chroma keying issue?

Gah, ignore me – it was my HDMI digitiser box doing something weird.

Heh, the Beeb used to shimmer an entire rainbow of colours on a telly in MODE 0.

Kind of amusing to observe that forty years have passed, and shimmer is still an issue. ;)

I had similar symptoms caused by a dodgy HDMI cable!

Degauss is your friend? Press the button a few times, once you have found it, by the way turning crt on and off will not do it. Bluish/purple haze was solved this way in 1997 for me.