The fact that this substance is an emulsion is chemically necessary, but fails to describe its most relevant characteristic: it contains crystals that harden when exposed to UV light.

That is cool! And why this substance works for stencil-making! Why isn't that mentioned in the name?

I'm sure scientists somewhere are like, "Actually, emulsions are cool." Emulsions are cool - ice cream and, like, a bunch of other useful stuff are emulsions. You can't use them to make screens for screen printing, though.

I do not have anything against emulsions. What I have an issue with is using the word "emulsion" to describe a very specific product that happens to be an emulsion. 

It's like calling bread "yeast." Yes there's yeast in bread -- some bread, anyway -- and it's an important component of making (some) bread bread. But there's also yeast in other products, like beer and Marmite and kombucha.  And you don't eat bread because of the yeast, you eat it because it's delicious.

Instead, we should call the substance used to create stencils for screen printing "UV light-sensitive crystal liquid." Or a different name that actually highlights the trait most pertinent to its most common use case.

Thank you for hearing me out on this very important matter. I appreciate your support. I'm going to eat some emulsion (of the ice cream variety.)