Our Premium Black cards are all about look and feel. We recommend keeping design details to a bare minimum for maximum impact - this means few colors (1-2) and graphics. Fine details and text are not legible in embossing, so we recommend very large sizes for any embossed text.
See: File Setup for Foil
Example of Artwork vs Final Product
Fine Detail
The finest detail recommended for foil stamping is 0.25pt line thickness.