In relation to your first comment: yes, quite; that was the point of my remark about materials quality.

In relation to your second, I'm certainly not someone who expects "usable results from random combos at the first attempt"; and of course, this particular recipe wasn't a "random combo", but a Kodak formula, although of course (again, as I am perfectly well aware) my materials are unlikely to be of the same grade as those used in a Kodak laboratory.