Texture in maps

This isn't much of a bug, as such, but is more something you may have overlooked.

On a map, blocks show up completely wrong, such as sand being a grey colour, I'm doing map art that i have spent weeks developing, so this is an issue for me. Even small errors like diorite showing up too dark is an issue as the map arts i am doing need it to be correct.

Thank you for reading and i hope you can fix this