Stearena Gamma, once a magi craftsman for the Celuroa Kingdom, had defected to the Shouro Empire years ago and later married the alchemist Toa Eschenbach.
She currently resided primarily at House Eschenbach, though she spent much of her time pursuing whatever research caught her fancy back on Hourai Island.
Saki Eschenbach, Toa’s only daughter, was now a capable adult in her own right. She had never raised any objections to her father’s marriage.
"Dear, how are things on your end?"
"Mmu. I’m trying a few different things with Saki’s help."
Toa was currently in the midst of a trial-and-error process, attempting to develop a blue dye.
"The juice from Purple Ganran only dyes things a pale shade, you see."
While the juice of the Purple Ganran—an anthocyanin pigment—could be shifted into various colors by adjusting its acidity or alkalinity, it was ill-suited for deep, saturated dyeing.
Saki had been roaming the hills and fields, collecting a variety of flora to bring home for testing.
"The flowers of this dayflower produce a beautiful blue, but their lightfastness is poor. The color fades almost immediately."
"Oh, is that so?"
"And these are the fruits of the harlequin glorybower, but their lightfastness is just as bad."
"I see... Could you not use blue stones? Lapis, perhaps?"
Lapis lazuli. It was the stone used to create the pigment known as ultramarine. Its mineral name was lazurite.
It was apparently called "ultramarine" because it was imported from "beyond the sea."
"That certainly is a beautiful blue, but it is a pigment. It isn't suited for dyeing cloth."
Pigments are coloring agents used in paints and lacquers; they have the power to obscure the base color of a surface.
Dyes, on the other hand, are used to penetrate and color fabrics or threads, and they have very little hiding power.
Furthermore, dyes are typically classified by their ability to dissolve in liquids like water, whereas pigments remain insoluble.
"It’s quite difficult, isn't it?" Stearena said, letting out a small sigh.
"Magical dyes are used for high-end fabrics and threads, but they are generally far too expensive for common use."
While Hourai Island possessed such dyes in units of ten tons, releasing that amount onto the open market would undoubtedly cause a massive upheaval.
"I want to find a way to produce an affordable blue dye."
"Yes, I understand."
"Dyes extracted from natural flowers fade easily. I suspect the fastest route would be to find a way to improve them."
"Indeed, that is one possible path," Stearena agreed, before offering her own opinion. "What about... synthesis?"
Toa nodded. "Mmu. That is the true essence of an alchemist."
One could say that alchemy was the primitive precursor to what is known today as chemistry.
"To create a synthetic dye that isn't a magical dye—that is also a goal of mine."
Just then, footsteps echoed nearby, and Saki poked her head into the room.
"Father... Oh, Stearena is here too."
Saki held out the basket in her hand.
"Father! I found these in Kaina Village. I think these berries could be used to dye things blue!"
The basket was filled to the brim with round, indigo berries.
"Apparently, they call them 'Aisugo' in Kaina Village. They're far too astringent to eat, but if you crush them, they yield a purplish-blue juice."
"Ho. That sounds like it’s worth a try."
Toa immediately placed some berries in a mortar and began to grind them. As Saki had said, a deep purplish-blue juice emerged.
Once filtered, it became a dark, saturated liquid.
When he dipped a small brush into it and wrote on a piece of wood-paper, the characters appeared in a satisfyingly dark hue.
"Hmm, this looks usable."
"Now it’s just a matter of lightfastness, Father."
"Mmu... Though, if I were to be greedy, I’d wish for a slightly more vivid blue."
Saki offered a suggestion. "Why don't you try testing the acidity and alkalinity?"
"Mmu, true enough."
Toa took a small amount of the juice into a separate dish and diluted it with water. There was no need for a high concentration just to observe how the color reacted.
"First, acid."
Using a handy acid, he dripped some vinegar into the dish. The purplish-blue water immediately turned red.
"Mmu, the same reaction as Purple Ganran."
Next, he added baking soda to a dish of diluted juice.
"Oh, this looks promising."
The purplish-blue had shifted into a vivid, bright blue.
"It seems baking soda is effective."
Currently, baking soda was extracted from natural sodium bicarbonate springs. The primary production area was located in the northern region of Kaina Village.
"What about lye?"
When he tested lye—which was cheaper than baking soda—the color turned a blue-green shade instead.
"Mmu... It seems this pigment is the same variety as Purple Ganran after all. I believe it was called 'anthocyanin'?"
Since anthocyanins turn green or even yellow in strong alkalis with a pH exceeding 13, it was only natural that the lye turned the solution green.
"So, it's a matter of adjusting the color with baking soda and then seeing if it can be fixed..."
Because the Aisugo berries yielded a very concentrated solution, it was practical for use, but the true obstacles were lightfastness and weather resistance.
No matter how well it dyed, it would have no practical value if it faded within weeks or washed out the moment it was caught in the rain.
"Um, would it be considered cheating to use magic to fix the color?"
Stearena, who had been silently observing the experiment until now, finally spoke up.
"Magic?"
"Yes. After all, the magi-craft spells Hardening and Toughening are ultimately just spells that strengthen the binding force of molecules to make them more durable, right? Isn't fading caused by the pigment essentially breaking down into a different substance?"
"..."
Toa and Saki both fell silent, ruminating on her words.
"Hrmm. It’s true that the color likely fades because the dye molecules are breaking down."
Saki added her own thought. "But Stearena, magi-craft spells like Hardening and Toughening strengthen the bonds between molecules, right? They don't make the molecules themselves harder to break."
"Yes, that’s correct. That’s why we just have to create a new magi-craft spell. One that makes the molecules themselves stronger."
She made it sound easy, but for an ordinary magi craftsman—as opposed to a Magi Craft Meister—creating a brand-new spell was an incredibly difficult feat.
However, Stearena was no ordinary magi craftsman.
"As long as the structure of the molecule itself doesn't change, it should work, right? The principle is the same as Hardening."
She fell into deep thought, her brow furrowed in concentration.
"Hmm... Atoms are what make up molecules, so if I strengthen the binding force between the atoms... Ah, but if I do that, I might accidentally change it into a different substance..."
Toa and Saki remained quiet, taking care not to disturb her focus.
"In short, I just need to envelop it in free ether and fix it in place... Fixation, huh? Let’s try it. If I do that..."
Stearena seemed to have hit upon an idea. To test it, she cast a new magi-craft spell, which she called "Stabilize," on some salt—sodium chloride.
"How is it?"
Stabilize was a spell designed to increase molecular stability. If applied to a water-soluble substance, it should—in theory—make it insoluble and resistant to decomposition by ultraviolet light.
True to her hypothesis, the salt treated with Stabilize would no longer dissolve in water.
"It’s a success!" Stearena nearly jumped for joy.
"Oh! If that’s the case, we can apply this to other pigments as well!" Toa exclaimed.
This meant they finally had a lead on how to make light-sensitive dyes commercially viable.
While it wasn't a solution independent of magic, they had finally found a path to making a practical "blue" dye.