Should you’ve examine the section over about metal foil stamping, the method might be straightforward to photograph. In the stack of components: your cover on The underside. Above it the (optional) foil then the steel stamp (die) which has a reversed version of your respective type or design sticking out. https://kindleselfpublish.home.blog/2024/09/28/creating-a-masterpiece-for-readers-through-the-art-of-book-formatting-and-layout/