Makeover by Min Kim.
Makeover by Min Kim.
"Katie hadn't touched her hair in over a year, since I highlighted it last," says Min Kim (@minkimcolorist), Master Color Specialist, Butterfly Studio Salon, NYC. "In the meantime her fine hair grew long enough for her to donate 12 inches to Children with Hair Loss." According to Kim, Katie is a low maintenance girl. "To create a natural and shadowed effect," the artist says, "the negative space increases vertically and horizontally as you work away from the face."
Here Kim shares the details for the makeover, using all L'Oréal Professionnel color (she is an International Artist for the brand):
STEP 1: Create 3 sections separating the back from the front and along the natural part line for the front. 
STEP 2: Back: In a balayage method, apply Multi-Techniques Lightening powder with 30 volume and Smartbond (mixed 1:2.5 ratio) using single points starting at the bottom of zone 1. Starting lower will create more negative space (depth) at the back of the head.
STEP 3: Front: single points around the hairline (for the most control on fine textures) starting in zone 1. 
STEP 4: Work 2 point pieces using diagonal back subsections (1.5" deep) from the ear up to the part line. Repeat on other side.
STEP 5: Pro tip: rinse the back as soon as the application is finished and increase the negative space as you work away from the face so the back piece in the front lines up with the single point pieces in the back.
STEP 6: Finish with a French gloss, formula: Dia Light (with 6 volume developer) 10.13 for 5 minutes.