Save your money and suppress the urge to use a box color and invest it at a reputable salon that has a colorist that understands how to use the color wheel. A good colorist knows that many times making the guest happy is about enhancing and suppressing existing colors. Sometimes the color applied isn't even the color the guest wants. Lets say you are a level 2 (darkest brown). The dominant color at this level is blue violet and say you want to move to a level 4 (brown) where the dominant color is red violet. Perhaps to get you to where you want to be at level 4 it is only the matter of suppressing some of the blue. On the color wheel, blue is suppressed by orange; Orange is a combination of equal parts of yellow and red. By using orange in the formula the blue will be suppressed and your red will be enhanced. If you wanted more enhancement of the red, a red orange would be used if you wanted less suppression of the blue, a yellow orange would be used. It would depend on what you communicated during the consultation with the colorist.
One of the least understood aspects of color is cool versus warm. Simply take a piece of green and orange colored construction paper and hold each under your chin while looking in a mirror with natural light. The reflection on your face from one will look significantly better than the other. If the orange reflection looks better, you need to go with a warm version of your desired color; green - a cool version. Getting this wrong will result in your new color not supporting your complexion. You will look either washed out or flushed all the time. A good color will make people notice your face first, hair color second.
If you have been using box colors, the colorist will probably want to do a color balance on you before applying any color. This is a mixture of clarifying shampoo and lightener. Its purpose is to strip out any un-oxidized dye molecules from previous applications that might react badly with the new color. If you have been using permanent box colors for years and have been applying it to your mid-shaft during touch-ups, the colorist may say there is nothing that can be done until it grow out. That is just the nature of box color.
