Every VirAR card works the same way: the printed photo is the trigger. When the phone's camera sees that exact image, it plays your video on top of it. Which means the picture you put on the paper is doing two jobs at once — it has to look good, and it has to be recognisable to a camera held at an angle, in a living room, in the evening.
What a camera finds easy
- Detail spread across the whole frame — texture, edges, small features in more than one place.
- Real contrast between light and dark areas, not a single soft gradient.
- An off-centre composition. A subject dead centre on a plain background gives the camera almost nothing to lock onto in the corners.
- Matte or dull paper. Gloss under a ceiling light throws a highlight across exactly the area the camera is reading.
What quietly makes it hard
- A large empty sky, wall or backdrop — beautiful, and blank to a tracker.
- Heavy blur or a very shallow depth of field: the sharp part may be too small a share of the image.
- Repeating patterns — stripes, tiles, a chessboard. The camera finds many matches and cannot tell which is which.
- Cropping in hard with a circular or heavily rounded mask and then zooming in. The corners the camera would have used are gone.
A useful test: squint at the photo. If it collapses into two or three soft shapes, a camera will struggle too.
The good news
Most ordinary family photos are excellent targets. A person in a room, a table with things on it, a garden — those are full of the kind of detail a tracker loves. The images that cause trouble are usually the deliberately minimal ones: a single object on a white background, or a strong colour wash with nothing in it.
If you are unsure, build the card and try it on your own screen before ordering. The AR layer works on a phone pointed at a monitor too — not as reliably as on paper, but enough to tell you whether the image itself is the problem.