In the black and white vs color scan question, the short answer is this: use black and white for plain printed text, grayscale for pages with photos, pencil or faint marks where color does not matter, and color for IDs, certificates, stamps, signatures in ink and anything where color carries meaning. Black and white gives the smallest and crispest file, color gives the most faithful copy.
The PDFNova Camera Scanner offers all three as filters, so you can switch and compare on the same page before you save. The rest of this guide explains what each mode really does, so you can choose with confidence instead of guessing.
What each scan mode actually does
Color
Color keeps the full picture as the camera saw it. Every point on the page stores its red, green and blue values. The result looks like the original, including paper tint, coffee stains and shadows. It is the largest of the three.
Grayscale
Grayscale throws away color but keeps brightness, from white through many shades of grey to black. Photos, pencil shading and soft stamps stay recognisable. The file is usually smaller than color because there is less information to store.
Black and white
Black and white, sometimes called monochrome or bitonal, forces every point to be either pure black or pure white. There are no shades in between. Text becomes sharp and high contrast, the grey paper background disappears and the file can be very small. Anything subtle, such as a photo or a pale stamp, may turn into blotches or vanish.
Black and white vs color scan vs grayscale at a glance
| Black and white | Grayscale | Color | |
|---|---|---|---|
| File size | Smallest | Medium | Largest |
| Printed text | Very crisp | Clear | Clear, background visible |
| Photos and shading | Poor | Good | Best |
| Stamps, seals, colored ink | Risky, may be lost | Visible but color is gone | Preserved |
| Uneven light and shadows | Can turn areas solid black | Shows as grey areas | Shows as they are |
| Printing cost | Lowest ink use | Low | Needs a color printer for full effect |
Which mode to use for common documents
- Typed letters, contracts, printed notes, book pages: black and white. It reads cleanly on a phone and prints well.
- Passports, national ID cards, driving licences: color. The photo and security print need to look like the original. For cards, the ID Card Scan tool places front and back on one A4 page at real card size.
- Degrees, transcripts and certificates: color, because seals, stamps and signatures are part of what makes them credible.
- Handwritten assignments in blue or black pen: black and white if the pen is dark and the light is even, otherwise grayscale.
- Pencil work, sketches, graphs with shading: grayscale. Black and white often erases light pencil lines.
- Receipts and thermal paper: grayscale. Faded print needs the in-between tones to stay legible.
- Forms with highlighted or color coded fields: color.
- Old photos, magazine pages, brochures: color, or grayscale for black and white prints.
- Bank statements and utility bills: black and white is normally fine, unless the organisation asks for a color copy.
When an application or office gives instructions, those come first. Some ask for color scans only. Check the wording on the upload page before you choose.
How to compare the modes on your own page
- Open the Camera Scanner in your browser and allow camera access when asked.
- Capture the page. The tool detects the edges automatically. Adjust the corners by hand if needed, and perspective correction will straighten the page.
- Apply the black and white filter and zoom in on the smallest text, any stamp and any signature.
- If something is missing or blotchy, switch to grayscale and look again.
- If color matters for this document, switch to color.
- Add further pages if you have them, then save the PDF to your device.
This takes a few seconds and removes the guesswork. New to phone scanning? Start with how to scan documents with your phone camera, which covers light, angle and focus. If you are replacing an office machine entirely, see how to scan to PDF without a scanner.
Scan mode and file size
Scan mode is the first and most effective way to control size. A text page saved in black and white needs far less data than the same page in color, because it stores only two values instead of millions of possible colors. Exact numbers depend on your camera, the page and the settings, so compare real files instead of trusting a rule of thumb.
If you need color but the PDF is too heavy to upload, reduce it afterwards with Compress PDF. The slider lets you pick a level and see the before and after size with a preview. Scans are image-based, so they usually shrink well. Our walkthrough on how to compress a PDF for free explains how far you can go before text suffers.
Scan mode and OCR
If you plan to turn the scan into searchable text with OCR PDF, clarity matters more than the mode itself. A clean black and white scan of printed text often works well, because the letters have strong contrast. On a page with shadows or faint print, grayscale may keep thin strokes that black and white would break. OCR accuracy depends on scan quality, so test one page before you process a long document.
Mistakes to avoid
- Black and white in poor light. A shadow across the page can become a solid black area that hides text. Fix the light or use grayscale.
- Color for everything. It is the safe habit, but it produces large files and shows every crease and stain on ordinary text pages.
- Black and white for IDs. The photo becomes a dark blob and the copy may be rejected.
- Mixing modes without reason. In a multi page document, keep one mode for similar pages so the file looks consistent.
- Not zooming in. A page that looks fine as a thumbnail can have missing decimal points or broken letters. Always check at full size.
Frequently asked questions
Is grayscale the same as black and white?
No. Grayscale contains many shades of grey, while black and white contains only two tones. Many printers label grayscale printing as black and white, which causes the confusion, but in scanning they are different modes.
Which scan mode gives the smallest PDF?
Black and white normally gives the smallest file, followed by grayscale, then color. The difference is largest on text pages.
Should I scan a signed document in color?
Color is the safer choice when a signature or stamp is in colored ink, since it shows that the mark is separate from the printed text. If the receiver only needs a readable copy, black and white is often accepted. Requirements differ by organisation.
Can I change a color scan to black and white later?
It is easiest to choose the filter while scanning, when you can compare the modes on the page. If you kept a color copy, you can always scan or filter again, but detail removed by black and white cannot be restored from that file.
Pick the mode for the document, not out of habit: black and white for text, grayscale for subtle marks, color for anything official. Try all three on your next page with the Camera Scanner and keep the one that reads best.