You need to rust them up first, and then dye them.
I just started trapping this year, decided to do it a week prior to the season opening. I bought two traps and blued them, ended up buying more traps as the season went on. I blued and or browned all of them, and just used them. Now that they have a good coat of rust, I will dye them in logwood dye.
I dont use that modern dip, but then Im using double long spring traps, some of them over 100 years old.....Logwood or even walunt dye is good enough for me.
Now the folks over on trapperman say you dont need to dye them for water sets, just set them and catch stuff. I did do just that on one trap, caught one very young beaver, and had the trap pulled out of the water by a coon that suffered a catastrophic amputation of one of its hands for its trouble......
So next year, they are all going to be blacked......