Business cards should be scanned on a high-contrast, text-free background. So place the lightest cards on a darker background - have a white sheet of paper for dark cards and a black sheet of paper (or similar) for white or light cards ready for the cut function to work.

White business card on the dark background: Cut function grabs the card (in red square), the business card itself is displayed in the backend.

White business card on light background: Cut function does not work, the whole photo is displayed in the backend, repeat scan on dark background for optimal results.