Stearina, a former magical craftsman of the Kingdom of Celuloa, once defected to the Kingdom of Shoro and later joined the alchemist Thore Eschenbach.

Now, she mainly lives in Eschenbach's mansion, and occasionally goes to Horai Island to pursue her favorite research.

Saki, Toa's only daughter, is now on her own. She had nothing against her father's marriage.

How are things going there?

"Yes. I'm trying out a few things with Saki's help.

Toa was now trying to develop a blue dye.

"The juice of the purple orchid can only be dyed a light color."

Although the juice of the purple ganoderma lucidum (anthocyanin as a pigment) can be changed into various colors by adjusting its acidity to alkalinity, it is not suitable for dyeing dark colors.

Saki went around the fields and mountains, collecting various flowers and plants, and brought them back home.

"The flowers of this plant turn a beautiful blue, but they are not lightfast and fade quickly," she said.

"Well, is that so?"

"This is the fruit of a flower called kusagi, which also has poor lightfastness."

"I see. I wonder if we can use ...... blue stones?　Like lapis."

Lapis lazuli. It is the raw material for a pigment called ultramarine. Its mineral name is blue gold (lazurite).

It was called because it was imported from across the sea.

It is indeed a beautiful blue color, but it is a pigment. It is not suitable for dyeing cloth.

Pigments are dyes used in paints and pigments, and have the ability to hide the underlying color.

Dyes are used to dye fabrics and threads and have little hiding power.

Dyes are soluble in water and other liquids, while pigments are not.

"It's a difficult one, isn't it?"

Stearina let out a small sigh.

"Magic dyes are used for expensive fabrics and yarns, but they are generally too expensive."

There are ten tons of it on Horai Island, but it would be a big problem to sell it on the market.

"I'm trying to find an inexpensive blue dye.

"Yes, I understand.

"Dyes from natural flowers tend to fade easily. I think the fastest way is to improve it.

"Yes, that is one way to go."

Stearina then adds her own opinion.

"And then there's ...... synthesis, right?"

Toa nodded.

"Yes. That's the essence of an alchemist.

Alchemy is a primitive form of what we call chemistry today.

"To create synthetic dyes that are not magic dyes. That is also our goal.

Then footsteps sounded and Saki appeared.

"Dad. ...... Oh, Stearena, you're here too."

Saki held out the basket in her hand.

"Dad!　I found these nuts in the village of Kaina, I think they can be dyed blue!

The basket was full of round, indigo-colored berries.

"In the village of Kaina, they call them . They are too bitter to eat, but when you crush them, they give off a bluish-purple juice.

"Wow. It's worth a try.

Toa immediately took a mortar and pestle and ground the berries. Indeed, a bluish-purple juice came out.

When he strained it, it turned into a dark bluish-purple liquid.

I put it on a small brush and wrote on a piece of wooden paper, and was able to write letters of a very dark color.

"Well, it looks usable," he said.

"Now all we need is lightfastness, Dad."

"Hmm. I'd like to use ......, but if I wanted, I'd have to make it a brighter blue.

Saki came up with an idea.

"Why don't you try acidic or alkaline?"

"Yes, indeed."

Toa then took a small amount on a separate plate and diluted it with water. He took a small amount and diluted it with water in another dish, because it does not need to be very thick to see how the color changes with acidity or alkalinity.

"First, acidity".

Vinegar, a familiar acid, is added to the water. The bluish-purple colored water turns reddish.

"Hmm, just like the purple-green orchid.

Next, he adds baking soda to the light colored water he made in another dish.

"Oh, this looks good.

Then, the blue-purple color changed to a bright blue.

"Baking soda seems to be effective.

So far the baking soda has been extracted from natural baking soda springs. The main source is in the northern part of the village of Kaina.

"What about lye?"

I also tried lye, which is cheaper than baking soda, and this time it turned blue-green.

"Mm...... this also seems to be the same kind of pigment as purple ganoderma. , you say?"

Anthocyanins turn green to yellow in strongly alkaline water with pH over 13, so it is not surprising that the colored water with lye turns green.

"So, can we adjust the color with baking soda and fix it? ......"

Since a very thick solution can be obtained from icego, it would be practical, but the problem is light and weather resistance.

The problem is light and weather resistance, because it is not practical if the color fades in a few weeks after being dyed or if the color fades when wet with rain.

"Hey, is it still wrong to use magic to fix the color?

Stearina, who had been silently watching the father-daughter experiment, opened her mouth.

"Magic?"

"Yes. The engineering magic such as or is a magic that strengthens the bonds between molecules and makes them more resistant to breakage, right?　Isn't the color fading because the pigment changes into another substance, so to speak?"

"......"

Toa and Saki ruminated over Stearina's words.

"Hmmm, it is true that the dye molecules break down, which may cause the color to fade."

At this point, Saki also opened her mouth.

"But, Mr. Stearina, the engineering magic such as or strengthens the bonding force between molecules, doesn't it?　It doesn't make the molecules themselves more difficult to break, does it?"

"Yes, that's right. Yes, that's right. So, we just need to create a new engineering magic. You know, the kind that makes the molecule itself stronger.

He makes it sound easy, but it is quite difficult for an ordinary magical craftsman to create new magic, let alone a <>.

However, Stearina is no ordinary magecraftsman.

"It is enough if the structure of the molecule itself is not changed, isn't it?　It's the same principle as ."

With that she began to think intently.

"Well,...... it's the atoms that make the molecule, so if we strengthen the bonding force between the atoms,...... then it might change into a different substance.... ..."

Toa and Saki decided to keep their mouths shut for a while so as not to disturb Stearina.

"In short, we can wrap it in free magic element (ether) and immobilize it. ...... immobilize it, huh? Let's try it. That would ......"

Stearina seemed to have an idea and tried applying the new engineering magic <> to the salt ...... sodium chloride.

"What do you think?"

<

And the salt that has been <> is now insoluble in water.

"Success!"

Stearina was so happy she could hardly contain her excitement.

"Oh, this can be applied to other dyes!

The fade-prone dye was now ready for practical use.

Although it could not be done without magic, they were on the verge of commercializing the dye for the time being.