Gaming AR Cards

[philip11]

what does the 3DS look for exactly in the cards?

 

[Ryupower]

maybe this
http://www.kotaku.com.au/2011/05/windowed-ar-cards-reveal-3ds-secret/
help

it looks for colors

 

[Snailface]

It reads color to know what card its looking at.

It reads the shape of that polygon in the background to determine the orientation of the card. (or the white borders maybe)

 

[Skelletonike]

But I'm pretty sure the 3DS could read black and white AR cards... *Goes to check*

Edit: Just tested it with this pic here and it worked just fine:

Spoiler

Both of them with gray tones worked just fine, try it yourself with those pics if you want.
I don't think the colors affect it, although there was a slight problem with it seeing as the ? card was mistaken for Kirby for a couple seconds.