What is the best material to choose for painting and calligraphy mounting frame?

it depends on the style of the mirror heart painting and calligraphy you prepared. If it is very traditional calligraphy or Chinese painting, it is recommended to choose dark wooden picture frames such as brown and red, and you can also consider using rounded corners, which is more beautiful. If it is a more modern style or western painting, you can learn from decorative picture frames or oil painting frames. Of course, it depends on your own aesthetic hobbies. You can consult and discuss with the painter who makes the frame. For reference only.