Triana asked me in the comments below for some advice to get perfect color results. So here are the following steps, I recommend:
First you need to bleach your hair to get a bright color. This step is very important, because there is NO PEROXIDE in the semi permanent colors. The bleaching will also roughen the hair structure and the color will be absorbed better. I'm using Schwarzkopf Blonde L1++ Extreme Aufheller Plus to bleach my hair. It is perfect, when you have dark hair, because it brightens up the hair about 6 to 8 nuances. Notice: The lighter the hair, the better and brighter the color.
Before you start with the color, make sure, all of the bleach have been washed out.
You can use disposable gloves and a brush for hair dye, you can buy them in every drug store. By the way you may also need some baby oil, petroleum jelly or cream to protect your skin and ears from getting dyed.
Wet your hair a bit and dry them with a towel. Now dye your hair strand for strand on every side with the color until your hair is thickly covered and let it process for at least 25 minutes. You can also mix the hair dye with some conditioner before you put it in your hair as you can see in the pictures.
Take care of your clothes, dripping dye can color them permanently.
So if you want to have permanently colorful dyed hair, you have to repeat the procedure from time to time.