Decapage is called the powder (pulp-cream) which is used in order to lighten the colour of the hair.
Actually, it is called decapage when it is used to lighten the colour of coloured hair and decolouration when it is used to lighten the natural colour of the hair.
For coloured hair: any time we would like to lighten the shade of the colour and the colourant itself is not capable of lightening the already coloured hair, decapage is needed in order to achieve the proper shade of the colour and then to apply the colourant to receive the desirable result.
For natural hair: when we would like to lighten the natural colour for more than 4 shades of colour and the colourant does not provide us with such a possibility, we use – in this case – decolouration and then we continue with the colourant or the colour refresher or whichever product we desire.