Word for the colored edges of book pages, opposite the spine

What is a word for the colored edges of book pages, opposite the spine. Is there a term for this?

I'm not looking for gilded or gold leaf, as those are both specific to golden edges, nor am I seeking a term used for especially ornamental usages. The question came to mind after looking at a math textbook that used blue color to highlight a supplemental chapter, so the usage was mostly functional.

Anyway, in case my description is lacking, here's a cool picture (a book's cover actually) showing some antique books that demonstrate rather elaborate edge designs.

Solution 1:

The coloured edge-pages are called, unsurprisingly, edge painting or fore-edge painting: that's actually already come up on a Stack Exchange site: Why do some books have colors on the edges of the pages?

Print Ninja corroborate that, and even call the speckled effect you see on some books fore-edge splatter. There are even people who do remarkably detailed work.

An edge mark which defines a particular section is called an edge index. This is produced slightly differently (by printing on the face of the page, at the edge, rather than on the closed edge) but has a similar effect.