hi all, I am doing a reno with a lot of NGRW doors, I had the doors striped and then the painter preped them, we have been using sikens oil and sealer, when first done they looked beautiful but over about a week everywhere they were exposed to sun a black mould like discoloration came out under the paint, since then on various pro advice we have stripped them back (paint stripper citris) and used timber reviver then intergrain timber seriliser and then bleach but the black stain keeps coming back through? I am woundering if anyone has had a similar problem? the assumtion has been that this is a mould in the timber but I an unsure as these get worse with uv exposure very quickly so maybe some sort of tanin reaction with the silkens paint or oil??? any help really appreciated as I have 12 NGRW doors that now look like ####