Really dark oil finish

I have an alder Strat that I finished with dark walnut Watco finish, and it came out sort of medium brown. I'd like to make it a really dark brown (not black). Anybody know of a product or method I can use to get this effect on alder? Thanks.

Welcome, Reif!

I would try adding dark brown Japan Colors to a small sample of Watco and see how that combination performs on a swatch of the same wood. You can probably get the whole body incrementally darker over time, adding additional layers of finish.

you could add some black dye to the oil and give it another coat.

Thanks for the idea. I think it will probably work. I assume I can't use the powdered pigments I use to tint lacquer? I also have some black liquid pigment that I can add to lacquer to make it black. My understanding is that the Japan colors are dissolved in oil, which of course would be compatible. Found a brand called Ronan.