I have gray roots and the remainder of my hair is light brown with dark brown ends. My hair is damaged from coloring and over pressing. I would like my hair to be a dark plum or auburn color and healthy. My natural color is dark brown. What kind of henna or combination should I use.?
Celebration will be your best bet as it has a very high dye content (3.4% lawsone), and yields a deep auburn color over time. Remember that multiple applications will be necessary for your grays to darken to the color you want. I have many gray hairs and I've been hennaing (with Jamila, Yemen, and Henna for African Hair) for years. All of my grays are now a rich, auburn color... gorgeous. The rest of my hair is fuller, shinier, and healthier looking. It's a rich, shiny black color indoors (with a few red highlights), and glows auburn in the sun... like a rinse.
When new grays come in or my roots show, I simply apply an overnight treatment, and after a couple of days, it oxidizes to a nice bronzey red. After another treatment, the roots match the length-- auburn.
For you, the key will be:
1. Four hour (or more) treatments
2. Multiple applications (for darker results)
3. Cleansing prior to application. Although I don't really do this anymore, if you have a lot of grays, this step is crucial. It will remove buildup and sebum, so that the dye can make the best contact with your roots.
Also, be sure to do lots of conditioning afterward to keep your hair moisturized, elastic, and supple. If your ends (and length?) are indeed damaged, and you're not interested in a Big Chop, you probably want to schedule some micro trims.
My aunt Toney has been a redhead since I can remember. She's naturally a medium to dark brown, but used boxed dyes to maintain a light auburn. A couple of years ago she transitioned to natural color with henna. Below is a pic of her shortly after starting henna (applying the paste to her grays and color treated strands).
This is a picture of her in February after many treatments. In person, her hair is a dark, rich, auburn (noticeably red indoors), and her grays (especially near her roots) are a shade or two lighter (similar to the darker parts of her hair in the pic above). It's an awesome color contrast and she gets tons of compliments.