I recently modeled a book, I wanted to start playing around with some textures to see what fits best. When doing so I noticed I wanted the leather bumps to look smaller and I couldn't make the UV any bigger to fit the image. Is there a way of doing this? Or is it the image I'm using?
If it is a tileable texture, then you can scale the uv outside the image boundary to greatly reduce the size of the individual details. If you then want to map decals or something else to the same surface, you can use another UV unwrap to get that mapping.
You can also change the size of the UV Map by changing the scale with a "Mapping" Node in the Shader-Editor.
This is a bit more elegant than just scaling up the UV-Map imo, it keeps the UV's a bit more tidy. It also allows to bake your texture later. With UV's scaled up and out of bounds of your image, you later can't bake parts that don't cover the image.