Hello Didier,
My apolgies for the late reply to your query but it took me quite some time to work out how to make a response.
Coming from a non member and a first time forum subscriber, I hope the following is what you need:
On my late Triumph TR4, Built in May 1964, the colour that remained on the oil filter canister closely matches Teal Green RAL 6019 but I understand Triumph did have a history of using what ever paint / colour were avaialble.
Cheers
John