I have been looking at using Sal ammoniac or ammonium chloride as its called for a rust blue project. I am a bit confused with the solution, the R.H Angier book says that the mix is 2% ammonium chloride but to mix with what? I guess it's distilled water at what %. Is it 2% of say a 100 grams of distilled water, 2% of what ever quantity of water you user. Can someone enlighten me.
