Artificial colour and propylene glycol.
Propylene Glycol, C.I. Number 42090
The non water based colours are the best choice for Fizzy Bath Bombs because they do not contain any water, only Propylene Glycol and the Artificial Colour.
The non water based colours are not light sensitive and do not discolour your sink or bath. Use 3-6 drops per 100ml. Add the drops to your blend and stir.
Note: The non water based colours are water soluble and not oil soluble.
Can easily keep without fading for 7 years in an airtight container; just don’t store them in direct sunlight, best stored in a dry and dark place.