Hennas do not enter the hair follicle like many chemical dyes. Instead, the henna coats the hair follicle on the outside. It forces the 'scales' of the hair follicle to lie flat, adding brilliant shine, and adds color over the natural hair color. So, as an example, if a blonde puts red henna on she will get a bright, brilliant, Lucille Ball red. But if a brunette uses the exact same henna, she would only have reddish highlights, and a slightly rosier shade. For some reason this concept is really difficult to explain to customers, so J and I are hoping that if we make a visual reference we will be better able to communicate the nature of the dyes to customers.
The hennas are sold in blocks, and you don't need much to do a strand test. I cut about an ounce of henna off the block, and ground it up. Then I added hot water until the henna was off a brownie batter-like consistency. I made sure to wear gloves so I wouldn't dye my skin, and then put the henna onto the different strands of hair.
You want to keep the henna warm while on your head to brighten the color and help it penetrate, so I figured I could bake the strands in the oven - but that seems like it would burn pretty easily, and burning hair smells AWFUL! - or put them outside in the sun. So the extensions have been in the backyard for two hours or so now, hopefully getting nice and colorful.
I should take photos. Let's see if I can find my camera, and (more importantly) figure out how to get the images off the camera and on to the Internet.