Ambergris Enameling

"So what is so important about these squid?"

"Not the squid. Well, the squid are important but what we are here for is--" Dark shapes suddenly come into view beginning to circle around the squid herding them like a dog would sheep.

"Porpoises." He finished. "We wait for em to eat then track them. Without the porpoises there is no enamel."

Ambergris enameling is a unique method of coating metals that rust or tarnish in seawater. It is an important process that allows for complex and energy intensive enchantments to be sustained underwater as most of the more effective alternatives are either land based fibers that are hard to acquire. Inks that require being on land to utilize making them inconvenient to handle and get a hold of or hair fibers that the only species that can be reliably found to use are mer and dragons which has ritualistic connotation reserved for family heirlooms and similar items. This leaves silver, which has the massive issue of tarnishing quickly on contact with seawater. While it is not the most corrosion susceptible metal it is hardly conducive to maintaining the delicacy of magical matrices over a sustained period. Thus the demand for an alternative or a method of protecting it without compromising on the readability of the matrices were high.
Eventually a mer metallurgist that was studying human smithing practices learned the art of enameling and set out to develop a clear enamel.
After years of research they discovered that a kind of silica based sludge that has deposits in some areas of the ocean floor can be refined into a clear and durable coating. Unfortunately this mixture while hardening just fine after heating, would not stick together or to what it was applied to.

Ambergris as a stabilizer

Ambergris is a waxy discharge produced in the digestive system of toothed whales that consume squid as their primary food source. This is mostly associated with sperm whales famous for huge chunks being excavated from beached specimens and washing up on shore. However the ambergris in question comes from crescent face porpoises who's preferred squid varieties have a particularly sticky slime which their astringent saliva is the perfect counter for. It was discovered during the development of underwater wax based molds that crescent face ambergris has an interesting property. When heated extensively both above water and under, crescent face ambergris hardens into a crystalline form similar in appearance to off white salt.
Further experimentation revealed that this property persisted when mixed with other waxes which is when it began to reach common discussion in research circles and was tested as a marine enameling stabilizer. First tests showed promising results only leaving some squid beak chunks and a mild off color both of which were fix via more thorough processing beforehand.

Harvesting

As far as cetacean molluscivores go crescent face porpoises are small, the smallest in fact. This is possibly the reason that they produce and expel ambergris at a much higher rate then other whales or perhaps it is a result of the unique chemicals in play from both the squids slime and crescent face's saliva. Whatever the reason it has allowed for reliable harvest of expelled porpoise ambergris via professional trackers finding either the pods of porpoises or their prey. The trackers simply wait about two days after the meal and they can collect it without much trouble.