This question was asked by
We have just had a driveway done and the flags are too light in colour (I like them when they are wet!) Looking to darken them up in a grey but need to know exact colour and maybe try them out first (I have spare flags to test on)
If the flags look ok when they are wet then all you need to do is apply a sealer, this will leave the flags looking like they do when they are wet and it will protect them from stains and general wear and tear.
I have linked a couple of products below (you didn’t say if they were concrete or natural stone flags) the first one is for concrete surfaces and the second is for stone.
Block Paving & Imprinted Concrete Sealer SP (BPCSP)
Drew Palin