What amazes me so often is no matter how much education we get, we still can get caught up on the names manufacturers put on the lines of haircolor. Names like permanent, semi-permanent and temporary with their textbook definitions can many times get in the way of the choices or options we may be considering. Like permanent means it's permanent or believing that temporary means it's going to always wash out in 1 shampoo! Never mind what Demi-permanent really means! The unfortunate part is I see color choices being made based on the name and not reality, even though we know reality!
Here's a scenario I always love to share: Let's say you had a guest whose hair was level 35 blonde (Level 35 blonde is when their hair is so blonde and so compromised that if they sneezed hair would probably break.) and you didn't fill their hair or treat their hair and you applied a permanent color. How long would you expect that to last? A week? A few shampoos? How about if that same person had sprayed their hair with a temporary colored hairspray black or green for Halloween? How long might that temporary color last? Forever? The reality is that the higher the porosity is, the less wearability permanent color might actually offer and the more permanent a temporary color can be.
The reality is that haircolor has been an evolution during the last century from non-oxidative colorants that dated back to Egyptian times to modern day colorants that create controlled oxidative results that can lift, deposit, cover gray and change the tone of the hair in one step. And now there are even direct deposit colorants that can offer permanent wearability because of new technologies, versus the last century, what haircolor can do has grown leaps and bounds. The big variant today though is much different than years ago and that variable has changed the outcomes.
Up until the sixties, porosity was predicable, everyone had normal porosity except for blondes who were porous and many with gray hair were resistant. Guests went to the salon once a week and had their hair shampooed and set, no flat irons, no changing of haircolor from brown to blonde to purple, green or gray! And even up into the 1950's coloring your hair was still a bit scandalous, with Clairol finally breaking through with the "Does she or Doesn't she" campaign and most young ladies still had virgin hair even after they were married. In the era we are in now, where even “virgin hair” has been flat ironed to within an inch of its life, the truth is all those descriptors like permanent, semi-permanent and temporary wearability was based on a guest that had "normal" porosity, which doesn't seem to exist anymore.
As if that wasn't enough to confuse a new beauty school student, in the late 1980's/early 1990's our industry gave us Demi-permanent colors and this further muddied what the color was and how long it would last. This became one of those confusing marketing scenarios, where a previous industry definition made it hard to define a new technology. Permanent colors historically were oxidative dyes that could penetrate into the cortex and do 4 things, controlled lift, deposit, cover gray and change the tone of the hair. While semi-permanent and temporary colors were non-oxidative that were intended to sit outside the cuticle or penetrate the cuticle and deposit themselves on the outer layer of the cortex without having the ability to lift or guarantee 100% gray coverage. Then we got Demi-permanent colors. They were oxidative, could penetrate into the cortex, change the tone of the hair, deposit, they offered gray blending or coverage depending on the line but they were not intended to give controlled lift, some don't lift at all. The challenge was most of these colors are basically permanent colors that aren't intended to give controlled lift, but because Demi-permanent and Semi-permanent are only 1 letter different so many of us were confused. The truth was Demi-permanent is permanent, it just doesn't lift in a controlled way so you can’t call it permanent even though the 4-6 weeks wearability is textbook permanent.
Sometimes temporary is really temporary and sometimes the temporary options are what I need to stain the hair and get permanent wearability! Because the poor permanent dyes just don't have the ability to hold on when there is that much porosity. So what color category will I use to get the best color results? That used to be a much easier answer to give, because today I don't know until I see the guest, touch their hair and do a consultation. Always remember that names can fool you, when you are looking for real world results.