[Chuckc]

I have been doing some reading in the book mentioned above. A lot of information written in a verbose style of Engish, but very interesting. Nothing in there that would point me towards the luger blue although it does give a Bern formula and some German origin formulas. There are limited attempts to describe the results, but nothing to tell me the subtle differences in the resulting colors.

I will now embark on a controlled experiment on old gun barrels to see what kind of results I get with different formulas and preps. Since no one offerd me a secret formula in off-forum communication and swore me to secrecy, I could offer the results on the forum. Anyone interested in the rusults?