How long do I leave Xora Cream hair color in for less blue more black?

I have Xora Cream Hair color products (blue black color and clear gel), how long should I leave it in for more black and less blue. Their sample looks realllllly blue I just want a slight tint...How long do I leave Xora Cream hair color in for less blue more black?
the time is not all it depends on you natural colour and the peroxide your using with it but anyhow if you want a black with a hint of blue well you should use the 1.8 with 6% peroxid if your natural colour is from 9 to 6 and 9% peroxide if from 5 to 4 if darker it wont work you'll have to bleach the hair first