Ketchum Ear Tattoo Letters - individual letters Tattooing is permanent, cost-effective identification. Ketchum permanent, antiseptic tattoo ink is spread on the area to be tattooed. Number, letter or custom designed tattoo dies inserted into the tattooer make small punctures in the skin. Ketchum tattoo in is rubbed into the puncture. The skin soon closes over the punctures, capturing the ink. The tattoo enlarges as the animal grows. All Ketchum tattooers feature the Lock-Bar method of character retention for fast, easy exchange of individual characters. No screws to undo. Characters stay in place when lock bar is open.