[KCV6]

There still has to be something else wrong or missing here. Chromates are chromates weather they come from Caswell or any other supplier. If it is just standard Olive drab chromate then it should work. I still don't understand the adding acid to get the PH to go up? As I said earlier, the more acidic a solution is the lower the PH number goes, you only add acid if you want the ph to go down. 0.2 is way too acidic. With any overly acidic chromate solution regardless of if it is gold, silver or olive drab, the items will come out blackish brown. A poor mans black chromate is to take old spent gold chromate and add hydroclauric acid to it to blacken the zinc as the chromate goes on (and for heavens sake no one try this as it will screw the solution).

Cheers

Mark