It seems pretty safe to assume that people have been making permanent marks on their bodies for a lot longer than we have the actual bodies to prove it. I’m sure our ancestors noticed that if you cut or puncture the skin (either accidentally or on purpose) with some sharp object that has some kind of pigment on it (anything from soot to red ochre) the mark stays after the wound heals. (Many a former grade school kid has the permanent mark of a pencil stab somewhere even today.)
After that discovery impinged on the general consciousness, some enterprising artist undoubtedly figured out pretty quickly how to make permanent marks on purpose, and body art took another giant step.
The first tattoo implements were likely things like thorns, sharp stone points and knives, and the colors those easily obtainable nearby. Soot makes good solid black marks; wood ashes rubbed into a wound would lead to scarring much more noticeable than if the wound were left to heal on its own. (Of course, rubbing such things into open wounds increased the chances of major infection, so perhaps each person who survived felt much more protected from the dangers of a primitive world.)
As people were able to make better carving tools, it became possible to carve fine-toothed tattoo “combs” and thus make larger marks all at once. Traditional Polynesian tattoo artists use this technique today. The comb is tapped with a stick to force the color into the skin, which got the work done a lot faster than poking individual dots with a thorn or sharp stone point. Traditional African tattoo artists still use the thorns.
People also used to use thread or sinew rubbed with pigment and “sewed” under the skin. This appears to have been the favored method among people in the arctic areas. This traditional method is not commonly used today, although there are still a few artists who know how to do it.
Advances in metalworking techniques helped as well. Up till fairly recent times, making needles was a labor-intensive process. Today’s machine-made needles are so common that we often don’t understand why people even a century ago had needle cases and had to make sure they cared for the needles they had as carefully as possible, re-sharpening them with emery if necessary (a reminder of this remains in the classic tomato-shaped pincushion with the little emery strawberry that people of my generation remember, and which is still being sold today). Being able to purchase relatively inexpensive needles for the purpose of tattooing, and being able to replace those needles easily should they get too dull or break, made life a lot easier for the artists.
With the advent of electricity, everything changed. Thomas Edison invented an electric engraving machine that was quickly adapted to “engrave” on skin, with a reservoir to deliver the pigment down hollow needles. At about the same time, a tattoo machine using electromagnets was invented, and this proved to be the superior design. Every advance in tattoo-machine technology since then has improved on that electromagnetic original.
I don’t think I would have had the courage to get an old-style tattoo. Even with the most modern technology the process is still painful. But at least it’s over a lot more quickly than it could once have been. And now more people can have traditional designs done with modern equipment, helping keep tradition alive in the Space Age. It’s one of the best examples of a combination of the old and the new.