A text document rarely needs millions of colors. If you're making a scanned copy of a form or a few pages of notes, storing all those shades can mean a larger file with little benefit.
Look Scanned now has a Black & White mode alongside color and grayscale. It turns each pixel into either black or white. For text-heavy pages, that can make the scanned PDF much smaller than a color or grayscale scan made with the same settings.
Already have a file to try? Open Look Scanned, add your PDF and choose Black & White under Scan Settings → Colorspace.
Black and white, grayscale or color?
People often call any scan without color “black and white.” In the settings, the two options do different jobs:
| Mode | What it keeps | When to use it |
|---|---|---|
| Color | Colors and their shades | Colored stamps, highlights, charts and photos where color matters |
| Grayscale | Shades of gray, without color | Faint handwriting, pencil notes, photos and shaded tables |
| Black & White | Pure black and pure white only | Dark text and simple line drawings on a light background |
Think of a table with a pale gray header. Grayscale keeps the shading. Black & White may turn it white. A dark colored stamp may still be visible in Black & White, but its color is gone. If the recipient needs to see that a stamp is red, keep color.
The new mode is 1-bit black and white, sometimes called bilevel. Grayscale is still available when those intermediate shades carry information.
Why can the scanned PDF be smaller?
A black-and-white page has just two pixel values to store. Look Scanned preserves that 1-bit image in the exported PDF instead of expanding it back into a full-color image. Pages with large white areas and dark text can compress well this way.
We tried the three modes on one A4-sized text-and-table sample at 150 PPI (1240 × 1754 pixels), using the Canvas engine in Chromium. Rotation, blur, noise, border and yellowing were off; brightness and contrast were unchanged. These are the downloaded PDF sizes, rounded:
| Same page, same settings | PDF size |
|---|---|
| Color | 193 KiB |
| Grayscale | 192 KiB |
| Black & White | 7.2 KiB |
That sample also had a pale note and gray shading behind the table header. Black & White removed the note and the shading, which helps explain the smaller file. This is one simple sample, not an average or a guaranteed saving for your files.
It is not a promise that every PDF will shrink. A small digital PDF may store text as text; turning its pages into images can make it larger, even in black and white. This mode is useful when you want a scanned-looking copy with less color information, rather than a general-purpose PDF compressor.
Page count, resolution, noise and the content itself all affect the result. Compare the downloaded file sizes using your own document before relying on an upload limit.
How to convert a PDF to a black-and-white scan
- Open Look Scanned and add your PDF.
- In Scan Settings, set Colorspace to Black & White.
- Check the preview, especially small letters, thin table lines and signatures. Adjust brightness or contrast if needed; switch to Grayscale if faint details disappear.
- Keep blur and noise low if a clear, compact text document is the goal. Use only as much resolution as the small print needs.
- In Output Settings, choose PDF, then generate and download the result. Open the saved file to check readability and size.
Need separate page images? PNG (ZIP) also preserves the black-and-white output losslessly. JPEG (ZIP) uses lossy compression, which can add gray pixels around edges; choose PDF or PNG when you want to retain the two-color result.
Standard scanning processes your PDF in the browser without sending the source document to a processing server.
What to check before sending
Black and white suits a plain text form. A page with pencil marks or a shaded diagram usually needs a closer look. Zoom in on the lightest writing, not just the large heading. If something meaningful disappears, keep grayscale or color.
Keep the original PDF too. Look Scanned renders pages as images and does not add an OCR text layer, so the output does not preserve the source's selectable, searchable text. If you're deciding whether you need a scanned copy at all, see scanned PDF vs editable PDF.
Try your PDF in Black & White and compare it with Grayscale in the preview. Choose the smaller result that still shows everything the reader needs.