After having your colour washed off, it is normal to then apply a toner. I typically hear questions like "why, has something gone wrong?" or "why do I need a toner?" so I hope this helps explain.
When we pre lighten (bleach) hair you are just lifting away colour pigments, no colour or tone is being put into the hair.
Once this has been rinsed off you are left with what we call a 'raw undercoat'.
This is your natural pigment being revealed as a result of lightening the hair.
Most often than not the raw undercoat can be red/orange/yellow (in various different shades and forms).
Toners come in all different shades, they can be used to enhance the natural undercoat that has been revealed, or can be used to tone out unwanted tones.
The most common use of a toner is to neutralise yellow/orange pigments, I still
normally use a toner on the hair if it has lifted to the desired shade and colour because it adds extra shine and colour longevity.
Your colourist should always thoroughly explain to you what effects this will have on your hair and what will happen when you go home and wash it yourself.
Toners DO FADE. How much they fade depends alot on your hair, the colour you have applied, the condition of your hair, and the products you use at home. This should be planned out in your consultation and you should be given the best home care advice, not only for the longevity of the toner but for the health and maintenance of your hair.