From photo to document: why your scanned PDF looks wrong
Grey paper, shadows, faded text. What actually happens to a photo of a document, and how the new files.co scanning tool fixes it.
You photograph a contract, drop it into a PDF, and the result gives itself away: the sheet is not white but a sad beige, there is a shadow down the left margin, and the letters look like pencil. It reads fine, but it does not look like a document.
files.co can now turn those photos into something presentable: Scan to PDF.
What is actually happening to the photo
Your eye corrects for lighting without telling you: you know the sheet is white, so you see it white. The camera does not. It records what is there, and what is there is paper lit by a warm bulb, or window light, or a greenish fluorescent tube. In pixels, that white is a grey sitting at 210 instead of 255.
Add the shadow you cast yourself leaning over the document, almost always down one side.
How it gets fixed
Not with a generic filter, because every photo has its own light. The tool computes the histogram of each image — how many pixels at each grey level — and finds where its real darkest and lightest points are. Then it stretches that range to the extremes: grey paper becomes white, faded ink settles into black.
That is the difference between crudely adding contrast and adapting to the specific photo you took.
Three treatments are available:
- Grayscale, the one that looks like an office scanner. This is the one we recommend.
- Black & white, with no greys in between. Smallest file, excellent for printed text.
- Colour, which respects the original photo, for documents where colour carries meaning — a stamp, a chart.
A practical detail: file size
A current phone shoots well over ten megapixels. Ten pages of that, dropped into a PDF untouched, gives you a file that will not fit in an email. Images are scaled to roughly 300 dpi on A4: the quality a document needs and not one byte more.
All on your device
The photos are treated in your own browser and the PDF is built right there. No upload, no server, no app to install and no weekly subscription hiding in step three.