I painted mine years ago to go with my counter top. Never had a problem with them peeling or anything. Ha and my brother said it wouldn't stay.... he was wrong. ( about 7 yrs now still looks nice )
Grout can be painted too, I did a light paint over my brick after I painted it ( dry brush technique ) to make it look like there was some grout was on bricks and make them look old . Good luck !
You can paint them for a different look
maybe update the look by painting them.
If you don't want to paint, try staining them. Test on a sample brick before doing the whole back splash.
would light stain work on dark brick. and to top it all it's got black mortar.
I painted mine years ago to go with my counter top. Never had a problem with them peeling or anything. Ha and my brother said it wouldn't stay.... he was wrong. ( about 7 yrs now still looks nice )