If it's paint, the best stuff used to be PJ1 sating black.
I did the barrels on my R1200C with that 6 years ago and it's still holding strong.
Only trouble is you can't get it anymore.
Something to do with pollution , environment etc.
It does sometimes turn up on ebay, at an horrendous price.
Shame.
Never found a worthy replacement
I used screwfix plastikote hot paint on my front cover. You have to get it hot soon after painting otherwise it stays like a powder and rubs off. Once it cures it stays on well and stands up to cow shit and mud. As with all spray paints, plenty of light coats rather than on thick one.