Best way for 12yo brunette to put a temporary colour in her hair?

[Rockbird]

As above really. She has very long brown hair and wants a colour in it but anything we've tried, like chalks etc doesn't show up. She'd love purple or blue but not sure what's best to use. Obviously I don't want to bleach it or use anything permanent, her hair is lovely as it is but she wants to do something while she's not at school. Thanks.

Coloured extensions? Maybe?

My dd is wanting the same (purple ideally!) and also brunette so I'm not sure anything would show.
I looked at some vibrant colour sprays on Clairs online before but there are no reviews.

Clip in extensions

Hair chalks are good fun and cheap. Lots of videos on YouTube

Hair chalk, non permanent dye, those hair mascara wand things from back in the day!

For a proper colour it needs to be bleached first. Just use chalks for now.

Following for ideas. DS is brunette but wants to go blue!

Manic panic semi permanent pillarbox red hair dye worked well for my 12 year old. It’s not a bright colour on her brown hair but enough to satisfy her.

My dd also with brown hair, has got me to dip dye her hair a couple of days ago. She chose a bright purple. It's not as vibrant as the pics online, but it's definitely visible. She is delighted!

You can't get vibrant colours on brown. The only way is to bleach first.

Mean to add, it was www.amazon.co.uk/PaintGlow-Semi-Permanent-Purple-colour-streaks/dp/B01NC2OXLG/ref=mp_s_a_1_5?dchild=1&keywords=purple+hair+dye&sprefix=purple&tag=mumsnetforu03-21&qid=1587837730&sr=8-5

But no gloves etc in there so be warned. We used one of the many carrier bags I have accumulated over the past 5 weeks to wrap around her hair and left it for 45 mins.

Also Arctic Fox dyes are good. Vegan, no peroxide, no ammonia . Only last a few washes. Not sure how they would show up on dark hair though

Thanks all, a few things to look at then.

@user1471530109 that looks fab, she'd be delighted with that!

I have dark hair and wear it multicolored. I use permanent dye but it only lasts about 6 weeks before starting to fade. You have to bleach it though, there's no way around it. I have mine done in a salon so it's quite expensive but I'm shit at doing my own hair. She doesn't have to bleach it too much though, just enough that its substantially lighter than the colour she wants to achieve. I have mine done every 3 months and don't have it bleached every time. I'd be bankrupt