We spec endpapers almost without thought: “80# plain, matching text” covers the vast majority of cases — maybe instances would be a better choice of word here. Thus if the book is printed on a white paper the binder will use a white endsheet — and if the book is on cream stock you won’t, we all hope, get a clashing white end. Almost all endpapers are 80 pound basis weight, heavier than the text stock, and thus stronger because nowadays the endpaper is, when all’s said and done, just about the only thing holding the book block into the case.
Of course every now and then, when the budget permits a bit of a flutter, we get a call for fancy ends. The least fancy would be a colored endpaper — Multicolor® is the one that sticks in everyone’s mind. It’s made by FiberMark in 90 shades and various textures (finishes which are embossed into the paper). Personally, though I do quite like many of the colored endpapers, I can’t really see a justification for the expense. I doubt if anyone’s buying decision was ever tipped from “Maybe” to “Yes” by contemplating the colored endpaper. I suppose it might be said to add to the impression that “this is a good book which the publisher cares about”. (If you have to save money, you’ll be looking at self ends.)
Printing something on the endpapers is often the next level of extravagance. Printing a pretty design can look nice, but always seems an indulgence to me, cheapskate that I am. Endpapers often carry maps, genealogical tables, mathematical formulae and other sorts of information which is “needed” in the book. I always think that if it’s really needed in the book it’s better that is should be printed in the book. Covers do fall off after all. Caveat: if you put something meaningful on the endpapers, you will encounter problems when you come to do the paperback, especially if you have to do a strip and rebind.
Marbled endpapers would be reserved for the most lavish of productions: I mean here properly marbled endpapers, where each one is unique rather than a printed version of a single marbled original. Atlas Obscura has an article about decorated endpapers with some nice examples.
The colors shown above are Multicolor® 70#, used for boxes etc. The 80# endsheet colors can be seen by using your mouse to scroll through the range at the FiberMark website. Of course screen color will never match the color of the paper itself (which of course will also change depending on the light source) so the only way to match colors, if you are wanting to pick up at the dominant color in the jacket say, is to look at a Multicolor® sample book.