Blackening of copper and tin & methods for tin plating

[Svet]

Hi guys, I am trying to copper-plate my (in)famous revolver and then blacken the copper plating to make it look like it was blued. Don't ask me why, it's just an experiment.
I am using cold gun bluing for the job. It does blacken the copper plating but it leaves a very slight, still noticeable, green tint to the whole look. In other words, what appears to be black is actually very, very, VERY dark green. I guess it is because of the formation of CuO which is naturally green.
My question is: is there a solution or a method that can make the copper plating look like real gun bluing? I mean, is there a way to make it look dark blue, dark brown or black but not dark green?
Maybe some stuff that does not rely on the formation of CuO but actually applies a new bonding layer of some other oxides/carbides/nitrates/whatever?

My other question is about tin plating.
How is fine tin plating done? I need a DIY solution because the commercial products used in the USA are not popular here, in Europe and because purchasing them online would be very unreasonable minding all the costs involved (VAT, customs taxes & shipping).
So again, I am looking for custom ways to apply quality tin plating to steel and/or copper.

And my last question is about blackening of tin.
I am using that same gun bluing solution that blackens copper for the job. It works OK, but I can't use it for immersion of large parts since it comes in small tubes of 20 ml.
Its other problem is that it makes tin dark grey, not black (like I want it).
Is there a DIY way to blacken tin? I mean to make it really, really black?

I asked same questions on Caswell Plating's forum (http://forum.caswellplating.com) but got warned by the moderators because they prohibit the posting of DIY recipies ont heir forum. Hehe, makes sence... maybe this is killing their business or something... Anyway.

Thanks in advance for your expert answers!

[guncrank]

Kit Ravenshear booklet "Metalwork Part 1" has formuals for coloring brass etc.
Good booklet recommend it highly. I got mine from Track of the Wolf.
His formula is Oxpho Blue cut with denatured alcohol. After a few days it will black brass.
Try to cut the bluing you are using may work as all cold blues use same chemical process (I think, not a chemist)
Not sure of tin may work as well.