How to photograph a document instead of scanning it

A form asks for a scan and all you have is a phone. A photo can become a proper scan if the shot contains what is needed. What can be fixed later and what cannot is decided when you press the shutter.

The habits below work for any scanner app and for a4norm, a free Telegram bot that turns a photo of a document into an A4 PDF. Where something is specific to Telegram, it says so.

1. The whole sheet in frame, with a margin

All four corners should be visible, plus a strip of desk around them. The edges are how the sheet is found in the picture and how its real size is worked out. A missing corner has to be guessed, and text that was cut off cannot be brought back by any processing.

2. A dark, plain background

White paper on a dark table is the easy case. On a pale patterned tablecloth or a pile of other papers the edge gets lost. A wooden table, a dark folder or a piece of cardboard will do.

3. Even light, no flash

Daylight by a window is best, but not direct sun. The flash puts a bright spot in the middle and makes glossy paper reflect, and where there is glare there is no text. A ceiling lamp right above the sheet is awkward too: you end up standing between it and the paper.

4. No shadow of your own

The most common mistake is a shadow of your head, hand or phone on the sheet. Step to one side, or turn the sheet so the light comes from the side. a4norm evens out a soft gradient of brightness; a hard shadow with a sharp edge it does not remove completely.

5. From above, roughly straight

Hold the phone parallel to the sheet. A slight angle is fine, the perspective gets corrected anyway. But the steeper the angle, the fewer pixels the far part of the page gets, and the blurrier the text there becomes.

6. Sharp focus

Tap the sheet on screen so the camera focuses on it, and hold still for a moment. Before sending, zoom in and check that the smallest print is readable. Blur cannot be removed afterwards.

7. Flat and uncovered

Smooth out folds. Keep fingers off the sheet: everything outside the sheet is erased, but a thumb on the page stays. One page per photo.

8. In Telegram: HD or send as a file

By default Telegram compresses photos so hard that small print suffers before any processing starts. Two ways around it:

• switch on HD when sending, or
• send the photo as a file via the paperclip. That is lossless, at the cost of a few more taps.

Send several pages of one document as one album. @a4norm_bot turns it into one multi-page PDF in the order of the photos.

What about certificates and applications?

Whether you may photograph a certificate instead of scanning it comes up on forums again and again. The answer depends on who receives it, not on the technology. uni-assist, for example, asks for scans saved as PDF that are complete and clearly legible. A straightened A4 PDF looks like what a flatbed scanner produces, not like a photo off the kitchen table. Whether it is accepted is still up to the recipient, and it never replaces a certified copy.

What processing can fix and what it cannot

With these eight points one shot is usually enough. If you already have photos and cannot retake them: turning an existing photo into a scan. And for documents for the Jobcenter there is a separate guide.