how are these achieved dark roots Blonde/ lighter ends e.g stacey solomon

[hanna]

Opinions on What is the best application to achieve this look? and what product? The darker roots /mid lengths then very light/blonde ends e.g Caroline flack (xfactor presenter) stacey solomon.
Any advice would be great i have a client who loves this look she is a base 6 with warm tones wants to get to a caramel blonde roots/mid lengths with the blonde ends? thanks:suprised:

 

[emmamb]

It's called 'ombre' if u do a search on here there's a few posts regarding method xx