Gene is correct - price is not the issue, quality is!
If you are looking to reproduce the original colors you need to find the gunsmith that specializes in that particular type of color casing. Doug Turnbull probably has the best reputation, and specializes in LC Smiths and Colts. I had a LC Smith done by him a number of years ago and it was perfect!
I have 2 kreighoff that a shop by the name of Signal Mountain Gun Shop in Roundup MT. They were blue receivers when I started the case colour, don't know if nickel will be a problem of not. The receivers turned out great, still have the k80. thanks Ronnie
Send the gun to Doug Turnbull - he has the Parker process pretty well mastered, and they come out beautiful.
The case coloring process was considered highly proprietary and a carefully guarded trade secret at the makers, and replicating it is difficult. Each process has its' own distinct characteristics, and it makes a big difference in how original the colors come out.
I did my Parker at Dougs', and it came back magnificent.
Another thought - when you case color, you are heat treating the receiver. This has to be done carefully to maintain the proper dimensions and not distort it. Keep that in mind - if the temperature and quench are not spot on, you could have some serious issues. That also goes for the packing (they pack the parts in charcoal - bone and stuff - that is part of the technique and color). If the over carborize by leaving it in the heat too long, you may not be happy.
I have a question. I had an old Double Barrel shotgun that looked like it was case colored. On the bottom of the reciever, it was worn shiny silver, from carrying it while hunting. Does this mean that it was fake case color, or is it normal that real case coloring wears through?
Some time back in the day, I contacted Doug Turnbull about doing case coloring on a Krieghoff Model 32 receiver which was due for a refinish. If I remember correctly, Doug advised me he either would not or strongly suggested against case hardening the Krieghoff receiver as he could not guarentee dimensions could be held after the process. I wound up sending it to Ottsville for a re-bluing.
What little I know about case coloring/ hardening is that the actual colors are a desirable by-product of the real intent. I think, that the whole purpose of carborizing the metal is to surface harden it for better wear and durability properties. It just so happens that it results in a finish that is very nice and classic. Even if the colors are long gone, the hardening is still there.
From what I've read, the fact that the surface is still hardened is the thing that makes restoring them so difficult, pricey, and risky. In order to properly color the receiver, it has to be annealed, and then the carborization / hardening / colorizing process can be re-done. This process is risky - even when done by an expert. Stick to someone like Turnbull that knows what they are doing.
I think it's probably a labor of love to restore a classic gun, and that you'll be lucky to come out ahead on the dollars side of the equation.
The Brits use a product called "Gunlock" varnish (sic) to protect the colors from fading or wearing off. If the gun gets frequent use, the process can be repeated and the colors will stay fresh and bright indefinitely.
I had the pleasure of a tour of the Doug Turnbull operation, upon my stay in NY last summer.
Unbelieveable to see those craftsmen at work...
I watched with amazement the fellow who was laying out the checkering to be done on a stock. Scribing, looking at it, scribing some more, looking at it again...I had never seen this done before, and was really interested...What a craftsman named Ryan Power...He just kept going like I wasn't even there, although he did say hello and was very friendly to me..I didn't want to bother him, just wanted to watch him with amazement.
Others were just as meticulous with their crafts...Amazing just isn't a complete word for what I saw...