How to See Through Cards

You can see through cards by using a special lens. These lenses have a purple filter that darkens the center of the lens. These lenses are available in a variety of tint sizes to suit different eye colors. They look normal to others but they allow you to see the luminous marks on the backs of the invisible marked cards deck.

The card reading system utilizes high resolution imaging to determine fine marks or problems on the cards and to register the rank and suit of each. The card image should be captured at one corner of the card. You can use polarized light to detect certain types of tampering or non-polarized to increase contrast to identify scratches and pinholes.

A UV filter or lens with a great coating can help reduce the ugly purple fringing that is caused by UV radiation. A good UV filter is especially important if you are working in a environment that has a lot of UV sources such as light bulbs. Avoiding scenes with high contrast and using a smaller aperture can also help you avoid this problem. If you cannot avoid this issue, there are several easy ways to fix your images in a program like Adobe Lightroom. It has a lens correction option under the Develop tab. This can be used to correct the problem, but it will also remove parts of the image.