Have a Miroku steel frame O/U Remington style derringer. The barrels are dark blue but the frame has tuned a plumb color. Is there any DIY method to return the frame to blue.
The early Colt Lightweight 1911 Commanders (Coltalloy, I believe is what the aluminum alloy was called) would turn purple. Thus, earning them the nickname, "Purple Ponies".
I dont recommend but Ive had to resort to heating up mix matches surfaces with torch then dunking in used diesel oil to fix blueing issues when the 3 different blueing solutions I have havnt preformed or done an good job. It can be very dark though but you can always rub back down with a cold blue and steel wool. Practice on something else first.
But as mentioned above that finish is very nice as is.
I would leave it, there is nothing wrong with a purple hue. Some Dan Wesson pistols used to do this as well and they would get the nick name Barney guns.
i would give the super blue a try buddy it turns it a lot blacker then the cold blue which turns it like grayish black color but that is from my experience and remember everybody uses different metals and alloys so look up your gun and see what type of metal its made of sir. like my tangfilo .25 is a made of zinc alloy and i tried reblue it came out sorta like the derringer in the picture but with less purple.
I do not mind the plum color. I found this a while ago when I came across a handgun whose frame had turned plum:
Hot tank bluing in nitrate salts is a controlled rusting process where the desired dark blue/black color is achieved by carefully controlled temperatures and solution concentrations. If the operator deviates even slightly from these controlled temperatures and solution concentrations, the result is plum or reddish color that can change as it ages. Bluing solutions wear out or get contaminated when used. Contamination occurs from drippings from rinse and cleaning baths. Improper temperature maintenance can leave the black oxide layer porous and subject to further micro rusting as it ages, with resulting color changes. Worn out solutions come from failure to carefully monitor solution chemistry or rushed production where the bluing bath is pushed beyond normal use.
Metallurgy, different alloys. Noticed it on different parts on HKs, usually the extractors.
IMO the only sure way to get completely matching colors would be a dura/cera-coat type spray on finish.
I too like the look of yours. 95 percent of the time (even now sitting in my pajamas) I have a .357 American derringer DA38 in my pocket, but it's S.S. to keep from wear, just have to keep the pocket lint cleaned out, lol