I have used the Brownells myself. When it first came out it was very much like Pilkington's. It seems to have become much stronger in subsequent batches I have purchased. I agree that it gives a nice deep black. I like a pretty mild solution and short rust periods to achieve a high luster blue. I have a bunch of chemicals on hand and it is a good day to do an inventory and see what I might need to order to start mixing my own. The thing I like about mixing my own browning solution is that it is repeatable. It seems like every solution acts slightly differently and you have a bit of a learning curve with each one.
