Hey ladies, I just went searching for info on semi permanent colors and here is what I found:
Caring for Semi Permanent Hair Color
By Anna Lynn Sibal
For the more adventurous of us, for those of us who like to experiment more with different fashion fads and different hairstyles, throwing ourselves into the foray of various hair colors as vivid and as multifarious as the colors of the rainbow is not an uncommon venture. Those who are gifted with bolder spirits in terms of fashion are not known to hesitate at highlighting their locks with unnatural streaks of magenta, purple, electric blue, orange or green, among other, more shocking shades. The brilliance of these colors reflects the brilliance and the vivacity of the beautiful souls who wear these streaks in their hair.
Such shades of hair color always come as semi-permanent, and because semi-permanent hair color fade more easily than permanent hair dyes, they need more effort towards maintaining their life and shine so they would last a lot longer.
Most women who go for semi-permanent hair color do this maintenance work by visiting their hairstylists on a weekly basis.
But not all women, adventurous spirits that they may be, can afford paying for a weekly visit to the salon. Thus, it becomes a necessity for the audacity to be tempered with a touch of practicality so that the adventurous woman with the brightly streaked hair can remain bold with her choices and yet not break her bank account.
How is this done? How can those vivid and vivacious semi-permanent streaks on those locks be preserved for a longer life without subjecting the hair to any damage? The secret to achieving a longer-lasting semi-permanent hair color involves diligence in caring for the hair. If you are one of those women who love to experiment with unnatural, semi-permanent hair colors, these tips are for you.
Right after the application of those bright and bold streaks, you should wash your hair with one part white vinegar mixed with one part warm water – a cup for a cup. In doing this, you are extending the life of your semi-permanent streaks by raising the pH level of the product through the use of the vinegar.
To prevent your colors from fading and from trickling down along with your sweat whenever you do some strenuous housework or go to the gym, wear your hair in a ponytail before you start doing your chores or working out. Also, wear a bandana or a hat before going out to prevent your colors from fading under the sun.
Because semi-permanent hair color needs weekly maintenance, have the product available at home so you can do your touch-ups yourself. You should pay close attention to the roots because color fades faster close to the roots. If the availability of time is your problem, then try to keep your bold colors as close to the natural shade of your hair as possible – if possible.
To keep your hair as free from damage as can be afforded by the use of semi-permanent hair coloring products, keep your hair moisturized. Use shampoos that are gentle and friendly to colored hair, the type that will not wash those pretty streaks away while you shower. Also, use detanglers and leave-on conditioners to reduce the friction created while brushing and combing the hair. This will prevent the hair from breaking and splitting.
I've bolded the fact that semi-permanent colors are safe to apply weekly, only look for the ones that have 'no ammonia and no peroxides' on the label.
Also here is the link to the above post -
http://www.2hairstyles.com/semi-permanent-hair-color.shtml. I agree with an earlier post too about using a coloring enhancing or preserving poo/conditioner or try the technique indicated in this article. HTH.