What color dye should I use?

Purple haze may seem reddish/warm on some pictures  online because to achieve cool-based purple you can't have warmth to your hair colour, which is quite hard to achieve and not everyone wants to risk bleaching their hair that severely.

If you don''t want to bleach your hair, it won't be as vibrant as with light blonde hair. Especially purple, you should have pretty much white hair if you want vibrant shade, as if you have any yellow, part of the dye will be "eaten" by the yellow bits, so they will turn to a kind of murky grey purple.

although I personally wouldn't consider these pictures you posted bright, they seem pretty toned-down, so You mighht actually get away with no bleaching at all...

That looks like a lovely medium purple shade (like Direction's old Plum formula).  You might be able to get something close to the bottom photo over your current hair; the top photo looks brighter and I think you'd need to do a quick bleach to get that shade.

Keep in mind that using semi colours tend to wash off more quickly on unprocessed hair, too, so you might need to top up more often than if you had lightened it.

As far as shades go ... I'd say either Adore Violet Gem, Manic Panic's Violet Night or Special Effects Pimpin Purple.  The colour will go darker than the swatch over hair that hasn't been lightened.

I think as long as you don't want it super vibrant you should be fine dying over your current hair color. However, you might find that the dye doesn't "stick" as well to virgin hair, and fades faster...but with a direct dye (semi) you can reapply it as often as you like without worrying about damage, as Intempestivity said.

There are ways to open the cuticle without bleach though, so if you find that it's not sticking, you shouldn't have to resort to bleach.

i bet you can achieve a nice purple over even a light brown base.  of the ones named so far, i've only used pimpin purple, but i LOVED it.  it's definitely my fav purple, and it is extremely forgiving in terms of your base-- i used to use it over other colors that i hadn't faded out all of the way, and it still came out really pretty.  i just want to warn you that while it starts out like the images you attached, pimpin purple *does* go pink as it fades.  ...i loved the fade, personally, but its worth mentioning, in case that's something you'd rather avoid.

edit to add**  i found pictures of my hair in some stage of a pimpin purple fade, just to show you.

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