How to chalk your hair :
Step 1: Wash hair
Shampoo hair with a clarifying shampoo. Skip the conditioner. Towel dry and comb out tangles.
Step 2: Pick your colors
Hair chalking on dark black hair is a fun way to give strands an artistic, temporary color kick. Pick one or more vibrant colors of soft pastel chalk from your local art supply.
Step 3: Get creative
Apply chalk heavily to selected damp strands focusing near the ends in an artistic fashion where desired. Steer away from hair chalking at the root or scalp.
Step 4: Be patient
Allow to air dry. Do not blow dry, as that will blow chalk off of strands and into the air.
Step 5: Seal the color
Once hair is 90 percent dry, seal chalked strands with a hot flat iron several times until completely dry, locking chalk onto the hair.
Step 6: Flaunt it
Now you are ready to go out for the weekend and flaunt you locks, but make sure to avoid getting caught in the rain and wearing white. Cobalt blue chalk looks crazy exotic on dark pigments. Hair chalking on dark black hair will only last two to three shampoos at most.