I have a quetion, and I would appreciate it if you provided me with some feedback/answers.
I'm working on a w/si liquid foundation, and I have been told by the suppliers of the formula's raw materials, that there is no need of checking the pH. Im thinking that it depends of the water, if it is external or internal phase. Could anyone explain to me when do we have to check it and when there is no need to do it?
Thank you in advance .