How to scan film negatives with your phone at home

You do not need a flatbed scanner or a lab to get your old negatives back. A phone camera, a bright white screen and one sheet of printer paper are enough for clean, shareable scans. The trick is in the details: light, distance, exposure and the orange mask.

What you need

• A light source. A tablet, a laptop or a second phone showing a plain white page at full brightness. A window on an overcast day also works, but a screen is more even and you can scan at night.
• A diffuser. One sheet of ordinary white printer paper, or tracing paper. It goes between the screen and the film.
• A camera. Any recent iPhone. On iPhone Pro models the macro camera lets you get close without blur.
• Clean film. A soft blower brush or a puff of air from a bulb. Do not wipe film with a cloth: grit scratches the emulsion.

Why the sheet of paper matters

A screen is made of tiny red, green and blue pixels with dark gaps between them. Your eye blends them; a phone camera a few centimetres away does not. Lay a negative straight on the glass and the camera records the pixel grid together with the picture, which shows up as moiré: a fine pattern of ripples over the scan. A sheet of paper scatters the light so the film sees a smooth white glow instead of a grid. Some people lift the film a few centimetres above the screen for the same reason; paper is easier and works every time.

On an iPad or iPhone used as the light, switch off True Tone and Night Shift. Both tint the white towards yellow, and a coloured backlight makes colour negatives harder to balance.

Step by step

1. Turn the room lights down. Overhead lamps reflect off the film and wash out the shadows.
2. Set the screen to full brightness and open a white page. Put the paper on top, then the film, emulsion side down (the duller side, where the image looks slightly raised).
3. Hold the phone parallel to the film, roughly 8–12 cm above it. Keep the strip flat; a curled strip goes soft at the edges.
4. Lock exposure on the bare film edge, the strip between the frame and the sprocket holes. That way every frame on the roll gets the same exposure and the colours stay consistent from shot to shot.
5. Shoot one frame at a time for the best detail, or the whole strip at once if you just want to see what is on a roll.

Turning the negative into a positive

Black-and-white negatives only need to be inverted: dark becomes light and the other way round. Colour negatives are different. Their base is not clear but orange. That orange layer, the mask, corrects for impure dyes in the film and was designed to be cancelled out when printing on photo paper. If you simply invert a colour negative, the orange turns into a deep blue cast over everything.

The fix is to measure the colour of the blank film edge, where nothing was exposed, and divide every pixel by it. After that the blank edge becomes neutral black and the picture underneath comes back with sensible colours. Then the levels of each colour channel are stretched so the darkest part of the image is black and the brightest is white.

Slides (positive transparency film, often in cardboard or plastic mounts) are already positive. They need no inversion, only a white balance against the backlight and a crop to the window of the mount.

Common problems

Problem	Cause	Fix
Ripples or a fine grid over the picture	Moiré from the screen pixels	Add a sheet of paper, or lift the film
Everything blue or cyan	Orange mask not removed	Balance on the blank film edge before inverting
Washed-out shadows	Room light reflecting on the film	Dim the room, avoid lamps above the phone
Each frame a different colour	Auto exposure changing between shots	Lock exposure on the film edge once per roll
White specks	Dust on the film	Blow the film off before scanning

How good can it get?

A phone scan will not match a drum scanner, but for family photos it is more than enough: a modern iPhone captures far more detail than a 10×15 cm print ever showed. If a frame matters a lot, keep the strip; you can always rescan it later with better gear.

Doing it with Negatone

Negatone does the inversion live in the viewfinder, so you see the positive before you press the shutter. Tap the blank film edge to lock focus, exposure and white balance, and the app removes the orange mask, crops the frame and saves the result to an album in Photos. The first 10 frames are free; a one-time purchase unlocks the rest, with no subscription.