Bad Girl Purple Storm is a semi-permanent direct dye, meaning it deposits pigment without lifting your natural colour. Because it contains no ammonia or peroxide, it cannot lighten hair — it only adds tone on top of what is already there.
Pre-lightened / platinum / level 9–10 blonde: You will see the clearest, most vivid violet-purple result, closest to the swatch on the pack.
Darker blonde / light brown (level 6–8): The shade reads as a cooler, muted purple cast that adds depth rather than a bright fashion colour. The underlying warmth of your base will influence the final hue.
Grey or white hair: With little underlying pigment to mute it, the colour often appears more intense and saturated than on pigmented hair.
Medium to dark brown (level 5 and darker): Very little visible change; at most a subtle cool sheen in direct light.
If you want a true vivid purple and your hair is darker than level 8, you would need to pre-lighten first. Always do a strand test on a hidden section to preview the result on your exact base.