"Are there even different kinds of lyrium?" wonders Stalas.
"It's hard to say. There are differences between different veins, but I haven't heard of any application where those differences become substantially significant."
"Insubstantially significant, though?"
"The difference between a very good rune and a perfect rune can rest on how well you understand and account for the slight differences between otherwise interchangeable materials. But to return to the subject of this lamp, it appears to cast a very weak light, which could potentially be a materials problem, but if I understand the thread of your conversation correctly, it is in fact casting a strong light that is visible only to plants?"
"Not necessarily. It would sunburn but not be any good for plants if it just did ultraviolet - plants actually do need visible light, just in all of the colors and really bright."
"I think that's the idea, yeah," says Stalas. "We don't know for sure."
"Then I would guess that the problem is not the materials but the process. A problem with the materials could produce a stronger or weaker effect, or make a rune fail entirely, but the process of crafting and the way in which the lyrium interacts with the substrate are what determine the nature of the effect."
"But wait, if it's the way the lyrium interacts with the substrate, then wouldn't the substrate matter a lot? Or can you do all the same things with, I don't know, soapstone, that you can do with iron, in the exact same ways? That sounds ridiculous. What if the smith picked up one thing when they wanted another? Would that be a materials problem or a process problem?"
"Stone and metal do require different processes, and different stones and different metals are different yet again. But while even I have been known to pick up the wrong stone once in a while, it would seem impossible not to notice... a very thoughtless smith might have used a different substrate than they intended, I suppose, and that could produce this kind of result while being technically an error of material as much as process. I do not know if that is what happened here, but it is an interesting thought."
"At any rate, exactly duplicating this lamp in particular won't do us any good but it's an important proof of concept that light runes can do arbitrary parts of the spectrum."
"And we should probably keep it in a box or something lest Annie get a - lamp-burn."
"I'm sure my regeneration can keep up with a little sunburn, but yeah." She finds a box.
"And then - should I tell you what colours all these lamps are so you can label them?"
Stalas describes the colour and brightness of every lamp. Greenish, bluish, purplish, pinkish, reddish, orangish, yellowish, and the weirder ones like the one that's really strongly blue and the one that's a mix of red and kerid, which is also the point at which Annie learns that the old dwarvish language has a basic colour word for infrared.
"Oh, that's right, humans don't see kerid. I forget if elves do but I remember learning that humans don't."
"Yeah. Now I'm really curious what it looks like. Oh well." She labels all the lamps and inspects them for patterns.
If she pores over the lamps a lot, armed with an understanding of how human vision works, she'll probably be able to make some pretty strong guesses about which variations on the basic textural pattern of a light-rune correspond to which frequencies of light. It's not exactly nice and neat, but there's a basis to work from.
"Maybe I should just make a ton of light runes," muses Annie. "At least as many as I did frost amulets. And see if any of them seem similar to these. Maybe if I layered a lot of different-colored ones it'd get a bright full spectrum lamp. I think the primary colors of visible light are... red and green and blue?"
"Multiple runes in a lamp sounds like a very promising direction," says Caridin. "It will be tricky, but you are an excellent student."
Caridin tinkers with his bicycle design and provides Annie with materials and advice. A productive time is had by all.
Annie spends a lot of time in the workshop over the next couple of days whenever she's not eating or sleeping or practicing sign language, making lights and many-runed lights and Slightly Incorrect In Various Ways Lights and getting confirmation from sighted people about their colors while she inspects their textural results.
Annie gets it, since Caridin cannot fit in the intervening passages. "Hello?"
"Are you Annie?" she asks. "My name is Metella Amell. Tev suggested I talk to you."
So Annie shows her in. "Are you going to talk to me about anything so interesting I shouldn't make rune lights at the same time?"