From red to blue, howhowhowwww??

I don't think it will be possible to get an obvious blue over your current colour. If you use a strongly pigmented blue such as one by Pravana or Special Effects you could get a dark navy/blue black that will look bluer in bright sunlight.

Yep, I agree. To get a blue to show (and even not go muddy) you'll need to be lighter with less orange/red.

You could do warmer colours though, reds/oranges/pinks, might be worth trying a heavily pink-based purple?

I don't want an electric blue. But possibly this color:

http://www.victorhugohair.com/2727-long-hair-hair-dark-blue-color/

I need to lighten another tone to have this?

Yes, definitely. You'd still need a pale, edging to mid, yellow. The more yellow the more green toned it'll be. My guess is, that was done on very light, to white, hair.

It's actually as hard to get that as electric blue. Electric blue is such a pigmented colour it's possibly easier to achieve. Blue can be one of the hardest colours to get because orange is it's opposite and so makes it muddy and yellow makes it green.

So i should bleach and maybe use an anti-yellow. But i don't want them flash!

Henna isn't easy to remove, so try a strand test before bleaching it all. It is unlikely to lift with bleaching though, henna is a truly permanent dye. There are methods that will lighten it, so do try searching, using oil soaks or plain peroxide are common methods.

Okay, i didn't know henna is permanent. haha i will try on some hair, maybe could exit a color that i like 🙂
Thank you everybody for advices! 🙂

Just wanted to add that the example picture is photoshopped; the girl's hair is actually a dark brown. There are pictures of her with Cruella teal/ purple hair as well that are 'shopped. You can always look through the gallery for hair color inspiration:

http://www.hairdyegallery.co.uk/Gallery-brand.html

🙂

Just wanted to add that the example picture is photoshopped; the girl's hair is actually a dark brown. There are pictures of her with Cruella teal/ purple hair as well that are 'shopped. You can always look through the gallery for hair color inspiration:

http://www.hairdyegallery.co.uk/Gallery-brand.html

🙂

Don't care if she used photoshop, i want that color 🙂
Thanks for the gallery 'photo by dye bran', very useful!

We get a lot of people requesting shades that are only available through photo editing, and not possible in real life.  It may be better to select a colour that is actually achievable, sometimes we need more realistic expectations if we don't want to be disappointed.
Here is an example of blue over a dark blonde base, much lighter than I think will be possible for you to achieve by bleaching out Henna.
http://www.hairdyeforum.com/index.php?topic=15096.0;topicseen