The difference between lightener and toner....

When you wish to lighten your hair more than 4 levels, a lightener must be used.  The term "lightener" is used in place of the term "bleach".  When you use lightener, you are lightening the hair.  Lightener can be used on color treated hair or it can be used on virgin hair.  It is fairly predictable in that it WILL lighten the hair.  Exactly how much it will lighten is always open to question.  Texture of the hair, how much previous color is on the hair, the consistency of the lightening product, how long the product is left on the hair, all factor into how well this adventure in hair coloring will turn out.  Using a product that is too thick will cause the product to dry out, making it relatively ineffective.  A product that is too thin will make a huge mess and won't spread evenly onto the hair.  When you have previous artificial color on the hair, the lightening product has to break that pigment up first, before it can work on the natural pigment.  And, sometimes, depending on how dark the artificial pigment is, you may not be able to lighten the hair to the desired shade before the hair disintegrates.

Lightener is a powerful tool in the hair colorists arsenal.  Too high a developer on the wrong hair type can ruin even the best work otherwise.  Knowing how to work with the product and being comfortable with the product are so vitally important.  Knowing how to work with it, but being uncomfortable with it won't get you terribly far...in fact, it will get you one less client in your chair because once you screw up a persons hair color, you won't get them back into your chair.  EVER.

Toner, on the other hand, is an entirely different product.  It is a product you use AFTER you lighten the hair to the acceptable tone of pale yellow (either the color of the inside of the banana or the outside of the banana, depending on A) what type of toner you are using, and B) what tone you're looking for.  Most toners currently in use do not have the ability to lift/lighten the hair what so ever.  What they are designed to do is change the tone of the hair.  For example:  You've lightened your client to a pale, golden blonde.  Her desire is to be platinum, which is a violet based, ash toned color...it's a cool tone.  So, what  you do is mix up the desired toner with it's dedicated developer, apply it to the hair, let it develop for the allotted time, rinse, and viola!  You should have platinum toned blonde hair.

However, when you use toner because you either grabbed it by mistake instead of grabbing high lift color (which, by the way, won't lighten hair levels 6 and darker enough), or grabbed it not realizing what the color actually was because you have no interest in reading the directions, or you're apparently still "suffering" from the effects of what you did last night, it won't do a bloody thing except possibly put a different tone on you current hair color.  And, as another "aside", mixing the shades of the toners together, particularly the violet toned one and the neutral/natural toned one won't really get you much of anything.  Except the need to ask for help (which should have happened in the first place), and for not being able to charge the client for your mistake, because, well, it was your fault in the first place!!