When incorporating digital signatures into a card's design, here are a few tips to remember for best results.
When you scan signatures to print on a plastic card, ensure that they are not too small or too thin. After you've captured the signatures, you may want to make some image adjustments in Photoshop or other photo editing software to ensure that they look sharp when you print onto PVC. Here are the two best ways to improve the crispness of your signature scans:
Image > Adjustments > Threshold...
Select > Modify > Feather... (Shift+F6)