How to take a photo the scan can read

The short version

If you only change three things, change these: photograph the document flat on a dark matte surface, in even indirect light, close enough to fill the frame. Most captures that keep failing are failing on one of those three.

The rest of this article is what to try when they are not enough.

Light

• Even and indirect beats bright. A room with the lights on, or daylight near a window, works better than direct sun or a single lamp pointed at the card.
• Do not put the light behind the document. Backlight makes the card a dark shape. The light should be behind you or above you, falling on the front of the ID.
• Watch for the hot spot. One strong light directly overhead puts a bright patch on a laminated card. Step to one side, or tilt the document a few degrees so the reflection falls away from the lens.
• Add light rather than using the flash. Flash on a glossy card usually makes glare worse. Turn on more room lights or move somewhere brighter instead.
• Avoid coloured light. A strongly tinted lamp or a screen lighting the card changes how the print reads.

Glare and reflection

• Take the ID out of its holder. Wallet windows, plastic sleeves, and card protectors add a reflective layer. So does a phone case with a card slot.
• Use a matte, dark background. A glossy table, a glass surface, a white countertop, or a patterned cloth all cause trouble. A dark book cover or a plain dark placemat works well.
• Check the preview for yourself. Your own reflection, the phone, and the ceiling light all show up in a laminate. If you can see them in the preview, the camera can too.
• Tilt a little, not a lot. A few degrees moves a reflection off the card. Too much and the document is no longer flat to the camera.

Framing

• Fill the frame. Get close enough that the document reaches the guide edges on screen. A small document in a large frame gives the scan very little to work with.
• Keep all four corners in. Close is good, cut off is not. Every corner should sit inside the guide.
• Hold the phone parallel to the document. Straight on, not leaning over it at an angle.
• Keep your fingers off the front. No fingertips over the photo, the text, or the barcode. Lay the document down, or hold it by the very edges.
• Clear the background. Nothing else in the shot: no second card, no clutter, no hands.

Focus and steadiness

• Wipe the camera lens. A pocket smudge softens every photo and is almost invisible on a small preview. This one fixes more blurry captures than anything else.
• Wait for the preview to sharpen before you capture. A phone needs a moment to focus after you move it.
• Brace yourself. Two hands, elbows on a table. If you can, set the document down and move only the phone.
• Do not chase the guide. Line the document up, hold still, and let the capture happen rather than moving the phone in and out.

The device

• Turn off Low Power Mode and charge the phone. Battery saving limits the camera and can stop a capture partway.
• Use the rear camera for documents if the verification flow lets you choose. It is sharper than the front one on nearly every phone.
• Close other camera apps, including video calls, so nothing else is holding the camera.
• Restart the phone if the camera has been misbehaving in other apps too.

What we cannot tell you

We cannot say what a check measures or why one particular photo did not pass. Publishing that would tell someone attempting fraud exactly what to imitate, which would make verification weaker for everyone it protects. Everything above is about giving the camera a clean, well lit, in focus view of a genuine document, which is the part that is yours to control.