How to Get Better Phone Scans: Lighting, Angle and Background Tips

Most bad phone scans have one of four causes: uneven light, a tilted phone, a background that blends into the paper, or motion blur. Fix those at capture time and almost any modern phone produces scans that are sharp, evenly white and easy to read. Filters and editing can help afterwards, but they cannot recover detail the camera never captured.

Here is what to change, roughly in order of how much difference it makes.

Get the light right

Light is the biggest factor. The goal is bright, even light across the whole page, with no hard shadows and no reflections.

• Diffuse daylight is best. A table near a window on an overcast day, or a bright room without direct sun, gives soft, even light. Direct sunlight creates harsh contrast and bright hot spots.
• Watch your own shadow. A single ceiling light directly above you puts the shadow of your head, hands and phone right on the page. Turn so the main light comes from the side, or step back and let a second light fill in.
• Use two light sources for tricky pages. Light from both sides cancels shadows, which helps with creased letters and curved book pages.
• Avoid mixed color temperatures. Warm lamp light on one side and cool daylight on the other gives a page that is yellow on one half and blue on the other. Filters struggle to clean that up evenly.
• Be careful with flash. Flash can rescue a dark room, but on glossy paper, photos and laminated cards it creates a bright reflection that wipes out text. On matte paper it can work well. Try one shot with and one without and compare.
• More light means less blur. In dim light the camera uses slower shutter speeds, and even slight hand movement smears small text. Turning on another lamp is often the quickest fix for blurry scans.

Hold the phone square to the page

Scanning apps correct perspective, turning a slightly trapezoid page back into a rectangle. That correction works best with small angles. The further you tilt, the more one end of the page is stretched from fewer pixels, so text at the far edge gets soft.

• Hold the phone parallel to the paper, directly above the center of the page. If your camera app has a level or grid, use it to check.
• Stand, do not sit, for full-size pages on a table. Standing over the page makes it much easier to get straight above it without leaning.
• Fill most of the frame, leaving a small margin of background around the page so the edges can be detected.
• Brace yourself. Rest your elbows on the table or hold the phone with both hands. For a big job, a phone stand or a stack of books with a gap for the camera gives perfectly repeatable shots.

Use a background that contrasts with the paper

Automatic edge detection looks for the boundary between the page and whatever is behind it. White paper on a white desk, or a beige receipt on a light wooden table, gives it very little to work with, and the crop ends up wrong.

• Use a dark, plain, matte surface: a dark notebook, a placemat, a dark tabletop or a sheet of black card.
• Avoid busy patterns. Wood grain, tablecloth patterns and printed newspapers under the page can confuse edge detection.
• Stop show-through on thin paper. Thin pages and receipts let the text on the back, or a dark background, show through. Slip a plain white sheet behind the page, inside the dark background area, to block it.

Focus, steadiness and resolution

• Clean the lens. Phone lenses collect fingerprints, and a smudge turns everything slightly hazy. Wipe it with a soft cloth before a scanning session.
• Let it focus. Tap on the text if your scanner allows it, and wait a moment before capturing. Auto-capture modes that wait for a stable frame help a lot.
• Get close enough for small print. Fine print, footnotes and receipt totals need the page to fill the frame. For small items such as receipts and cards, move in closer rather than relying on cropping later.
• Use the main camera. On phones with several rear cameras, the main (wide) camera usually has the best sensor. Ultra-wide lenses distort near the edges.

Tricky paper and how to handle it

Item	Problem	What helps
Thermal receipts	Faded, low-contrast print that keeps fading over time	Scan soon after purchase, use grayscale or an enhanced filter, and get close
Glossy photos and brochures	Reflections	No flash, light from the side, tilt slightly
Creased or folded letters	Shadows along folds	Flatten first, use light from two sides
Bound books	Curved pages, dark gutter	One page at a time, glass sheet to flatten, light the spine
Whiteboards	Glare, gray background, faint marker	Shoot straight on from a distance, then use a whiteboard filter
Pencil handwriting	Light gray strokes vanish in black and white	Use grayscale rather than pure black and white

For long documents and books specifically, see our guide to scanning multi-page documents and books.

Choosing the right filter after capture

Filters do not add detail, but they can make a good capture look much cleaner:

• Black and white turns paper pure white and text pure black. It is the cleanest and smallest option for printed documents, but it can wipe out light pencil, colored stamps and highlights.
• Grayscale keeps shading and faint strokes, which suits handwriting, pencil and faded receipts.
• Enhanced color boosts contrast while keeping color, which is useful for forms with colored fields, signatures in blue ink and stamps.
• Whiteboard filters turn a gray, glary board into a white background with saturated marker colors.
• Original keeps the photo as captured, for when color accuracy matters more than cleanliness.

If you are unsure, compare black and white and grayscale at full zoom on the smallest text. The choice also affects file size; our guide to reducing scanned PDF file size explains by how much.

Putting it into practice in OnlyScans

OnlyScans does a lot of the cleanup for you, but it still benefits from good light and a dark background. On Android:

• Capture: the default scanner detects page edges, corrects perspective and can clean up smudges and shadows. If you prefer, turn on Use alternative camera scanner under Settings, Scanner, and enable Auto capture when page is detected, which takes the shot only once a stable page outline is held.
• Fix the crop and angle: each page's Adjustments sheet has a Crop tool with corner handles and a rotation control with 90-degree turns and a Fine tune setting for slightly crooked pages.
• Pick a filter: the same sheet offers Original, Enhanced, Grayscale and B&W presets per page, and the export screen's Global Filter adds Whiteboard and applies your choice to every page. Filters are free.
• Fine-tune: manual Brightness, Contrast, Saturation and Sharpness sliders sit in the Adjustments sheet too. On Android the manual sliders are part of Pro.

The iPhone version has the same five filters and a matching adjustments sheet with crop and rotation. Everything runs on the device, so you can rescan and retry as often as you like without uploading anything. For receipts in particular, our sister site has a dedicated receipt scanning guide.

Frequently asked questions

Why do my scans look gray instead of white?

The page is underexposed, usually because of dim or uneven light. Add light, or use a black-and-white or enhanced filter to push the background to white. Fixing the light gives the best result.

Should I use the flash when scanning documents?

On matte paper in a dim room, flash can help. On anything glossy, it usually creates a bright reflection over the text. Try both and keep the better shot.

Why does edge detection keep cropping my page wrong?

The page and the background are too similar, or the background is patterned. Put the page on a plain, dark surface and leave a small margin of background visible around all four edges.

How do I stop the back of the page showing through?

Put a plain white sheet directly behind the page you are scanning. A black-and-white filter also helps hide faint show-through.