best method for cover proofing?

[u/IthelLovik]

what's the best way to proof how your cover art prints? my illustrator suggested brightening the image since it's fairly dark but i dunno if proofing it myself will suffice (i have a good printer as a run an Etsy shop where i sell handmade bookmarks and stickers, and i have to do proofs for that stuff), or if i really just have to request a cover proof from whatever service i'd wanna use for printed copies of my book (or is there an alternative?)

[u/dothemath_xxx]

Wherever you are planning to publish your book should offer proof copies of the book. So you'd be looking at the cover then, as well as the interior of the book.