By the middle of the sixteenth century the techniques of the armorer were fully developed. From the smelters he was able to obtain iron in good-sized lumps, and he had learned so to weld it as to produce plates of any desired size. He could keep it soft and malleable or could add minute amounts of carbon and thus convert it into steel, which he could, by heat treatment, give any desired degree of hardness. He no longer bothered to harden the surface of his breastplate and helmets to the glassy hardness which was the pride of the Gothic armorers, but he made good, reasonably homogeneous mild steel which was hard enough for sword or dagger blades, yet tough enough to avoid brittleness. He could hammer his metal into even the most fantastic shapes, could color or gild it, or could inlay it with precious metals. Armorers began to vie with one another to produce magnificent and elaborate armor; many and strange were the results. Instead of only one kind of armor, as in the past, there were three: military, tournament and parade armor. In the military armor, intended for actual fighting, taste was usually conservative. Extravagances, such as excessively wide or narrow sollerets, over-elaborate elbow guards, or extremely large shoulder guards, were avoided. A moderate amount of decoration was considered quite permissible, provided it did not lessen the functionality of the armor; such decoration most frequently was in the form of etching. [Illustration: _Fig. 11. A breastplate decorated with etched ornament against a black background._] [Illustration: _Fig. 12. A morion with etched decoration. Handsome, but rather top-heavy._] Although we are accustomed to think of etching primarily in connection with pictures on paper, the process seems to have originated with the armorers. They would take a helmet or breastplate, paint it all over with a heavy acid-proof varnish, scratch a design through this varnish with a sharp needle, then place the metal in a bath of acid. The acid would eat away the steel where the varnish had been scratched, but not elsewhere. After the plate had been taken from the acid and the varnish removed, the etched part would show dark against the polished surface of the steel. This contrast could be heightened by rubbing in a little black pigment, and the early armorers discovered that they could readily keep a record of their work or a sample sheet to show other customers, by simply placing a piece of paper against the etched and blackened surface and rubbing it. The fresh black would stick to the paper, giving a clear impression of the etched design. Masters of etching like Rembrandt used and modern etchers still use essentially the same process. [Illustration: _Fig. 13. A closed helmet with etching. Though heavier, it is more comfortable than Fig. 12, since its weight rests partly on the shoulders._]