mixing hair dye

Technically, yes, but Ebony can be tricky. The problem is, there's no black without being a super concentrated version of another colour, often green or red/brown. These colours can just make the colour you're mixing more muddy.

How dark do you want it? Is there a reason you want to use dark tulip? Maybe another colour might be better instead.

Thank you for your advice.
I had my hair done about 3 weeks ago.Had it lightened and roots done dark brown then she put a very deep dark permanent colour on the rest, it was like a dark aubergine kind of colour. On the lightened bits she then used a Fudge Raspberry Berret colour and I like it but its abit pinky plum for me.
Hairdresser mentioned that there was a directions dark tulip colour that I could use but I've seen it online and that looks a bit pinky plum too so I would like to make it darker like an aubergine type colour. I've only looked at the directions and fudge types as those are the ones she has mentioned. Thanks for your help.x

So you want a more blue toned colour? If I'm right, you might want Directions Plum with some pink added.

Best thing would be to use Plum, dilute it about 60/40 with conditioner (it's REALLY pigmented and will bleed colour for a long time if put on undiluted) and then mix in a little pink. Dark tulip would be fine.

Thanks so much.
Aiming for a colour along the lines of the picture attached, really deep and dark.