Pillarbox Red Semi-Permanent Hair Colours A classic colour with uncompromising brightness, Pillarbox Red is just as vibrant as its name suggests. For the most vivid results, we recommend applying to pre-lightened hair. The colour on the pot is a simulation of the colour on a level 10. Soft, silky hair never goes out of style. That’s why all our colours contain a conditioning formula that nourishes hair from first application.