I'm trying to find my recipe book and resultant prints so I can get you closer (it's here somewhere but temporarily lost) meanwhile I can say that what you will need to do is some test strips but don't use a negative. Remember also that part of the solution is longer exposure times, so mix the minimum needed chemicals and leave the test strip in the sun, not under a lamp. Use Ammonium Dichromate, Ammonium Ferric Oxalate and Palladium, nothing else. I can say that 1 drop 5% gold chloride solution get's you into cool blue-blacks. From what I remember, for a 4x5 test print start at 1 drop 5% GC. I wound up diluting the 5% down.