---
title: "How to convert a film negative on a Mac or PC, step by step"
description: "How to convert film negatives on a Mac or a Windows PC: add the folder of scans, follow Prepare the Roll, touch up and export. Free, no account."
url: "https://open-negative-initiative.com/guide"
---

# How to convert your film negatives, in four steps

**Your folder of scans becomes a roll of finished photos.** Bring the scans in, follow Prepare the Roll, touch up if you want, and export.

![White cliffs meeting a blue sea, seen from the air, a line of foam along the shore.](https://open-negative-initiative.com/media/carousel/aerial-cliffs-1400.webp)

![The raw scan of the cliffs: the sea is orange-red, the cliffs dark, the foam a dark line, under the orange base.](https://open-negative-initiative.com/media/carousel/aerial-cliffs-raw-1400.webp)

**Aerial cliffs, Kodak Gold, converted in Open Negative Initiative.**

## What you need.

**Your scans, and your computer.** Nothing else, and no account to make.

- **Scans of your film.** From a camera over a light panel, or from a film scanner. Prepare the Roll asks which, and reads three passes under red, green and blue light too.
- **A Mac or a Windows PC.** macOS 13 or later on Apple Silicon or Intel, or Windows 10 or 11 (64-bit).

### Before you start: scanning with a camera.

Lay the strip flat over an even light panel, shoot it in RAW with a macro lens at base ISO, in manual exposure so every frame gets the same settings, and take one shot of the empty panel: Prepare the Roll uses it to even out your light.

## Step 1: Bring your scans in.

**Open the folder that holds them.** Nothing is imported or copied, and your originals are never written to.

![The gallery: a folder of scans opened in rows of frames, ADD FOLDER… in the bar, and on the right the selected frame's roll: its name, film stock and shot date.](https://open-negative-initiative.com/_astro/gallery.CPXWUEzH_1ygMTW.webp)

- **Press ADD FOLDER…** in the gallery's bar and pick the folder of your scans. It joins your favourites, its subfolders with it.
- **Or choose Open Folder…** in the File menu (`⌘O`, or `Ctrl+O` on Windows), or drop the folder on the window.
- **Make one film a roll.** Select its frames: the column on the right asks for a name and a stock, then **MAKE THIS FOLDER A ROLL**.

## Step 2: Prepare the roll.

**Five short steps, then Measure.** Open a frame of a roll never measured and Prepare the Roll starts on its own, or press PREPARE ROLL in the gallery's bar.

![Prepare the Roll on its last step: the measuring frame drawn inside the picture of a scan, the Frame slider on 1 of 9, and MEASURE 9 FRAMES.](https://open-negative-initiative.com/_astro/prepare-roll-frame.DyPFFh7E_863ar.webp)

- **Say what your film is.** Negative, Positive for slides, or B&W, and what you digitised it with: DSLR Scan is chosen when the roll opens, and a scanner skips the flat-field.
- **Even out your light.** Click the shot of the empty light panel, then **USE THIS FRAME AS FLAT-FIELD**. Press SKIP if your light is even.

- ![The loupe over the bare orange film of a scan, its ring on the spot the click reads.](https://open-negative-initiative.com/_astro/prepare-roll-base.Cl6W2Vr6_2kqHyo.webp) **Click the bare film.** Choose a scan and click its border or the gap between two frames, under the loupe. On a roll of slides, click a white or grey instead, and the flags step is skipped.
- ![The roll as a sheet of frames, one of them marked FLAGGED in red.](https://open-negative-initiative.com/_astro/prepare-roll-flags-marked.CKPKARJM_1sIyek.webp) **Flag the odd frames.** Light leaks, the cut first frame, extreme shots: they are still converted, but never weigh on the roll's measurement.
- ![A scan with the measuring frame drawn inside its picture, clear of the film's edges.](https://open-negative-initiative.com/_astro/prepare-roll-frame.DyPFFh7E_863ar.webp) **Place the measuring frame.** Draw it inside the picture, clear of the holder and the film's edges, check it on every scan, then press MEASURE.

## Step 3: Touch up, if you want.

**Your frames open already converted.** Measure opens your whole roll side by side, like a contact sheet. A change there lands on every frame: press Auto White Balance to give the roll one look. To correct one frame alone, select it on its own: it opens by itself.

![The Open Negative Initiative editor on the Color tab: a converted night photo of glass lift lit green on a Paris pavement at night on the canvas, the frames of the roll on the left, and on the right the histogram, AUTO WHITE BALANCE and the colour and exposure sliders.](https://open-negative-initiative.com/_astro/editor-color-negative.BPHj9Uhs_ZacVtI.webp)

- **Press Auto White Balance.** It reads the light of your frame and sets Temperature and Tint so that light prints neutral.
- **Retouch it by hand.** Temperature and Tint then move like any other value.
- **Set how light it prints.** Exposure reads in EV: a full stop in the shadows, while the highlights roll toward white.

## Step 4: Export.

**Your frames, written as photos.** The export screen writes your whole selection in one go.

![The export screen: the converted night photo of a glass lift in the middle, the Instagram, Display and Print presets at the top of the right column, and EXPORT at its foot.](https://open-negative-initiative.com/_astro/export.BMlaRCCq_2sAfCc.webp)

- **Open the export screen.** Select your frames and press EXPORT in the bar, or `⌘E` (`Ctrl+E` on Windows).
- **Start from a preset.** Instagram, Display or Print fills every field at once; change any field after.
- **Pick the format.** TIFF 16-bit keeps every tone, JPEG is read everywhere. A batch asks for a folder, and your originals are never touched.

## If it does not look right.

**The usual fixes, in a sentence.** Each one links to its page of the manual.

### One frame prints darker than the others.

The roll's white is set near its brightest frames, so a frame shot darker, or a thin negative, prints lower than the rest. Raise its [Exposure](https://open-negative-initiative.com/manual/color#lighting-exposure).

### A frame keeps a colour cast.

Press [Auto White Balance](https://open-negative-initiative.com/manual/color#auto-white-balance), then retouch Temperature and Tint. [Balance Strength](https://open-negative-initiative.com/manual/roll#balance-strength), in the Roll tab, sets how much of the correction they take.

### The corners are darker, or tinted.

Uneven light does that to every frame. Shoot the empty light panel on the same rig and use it as the [flat-field](https://open-negative-initiative.com/manual/roll#flat-field-switch), in Prepare the Roll or later in the Roll tab.

### Every frame of the roll looks wrong.

Check the [film type](https://open-negative-initiative.com/manual/roll#conversion-mode): the wrong one converts every frame of the roll wrong. It changes in the Roll tab, for the whole roll.

### The whole roll should share one look.

Copy Settings on one frame, then [Paste to Roll](https://open-negative-initiative.com/manual/presets#preset-copy-paste) lays its Color and Details tabs on every frame of the roll. The crop never travels with them.

### What should a converted roll look like?

Compare yours with real film scans converted in Open Negative Initiative, each beside its raw scan. [See what a converted roll looks like](https://open-negative-initiative.com/gallery).

## Convert your first roll tonight.

**Add your folder, prepare the roll once, export.** Free, and nothing else to install.

[Download for Mac](https://github.com/5e1y/open-negative-initiative-releases/releases/latest/download/OpenNegative.dmg) · [Download for Windows](https://github.com/5e1y/open-negative-initiative-releases/releases/latest/download/ONI-windows.zip)

[How to convert a film negative, step by step](https://open-negative-initiative.com/guide)

- **Mac**: macOS 13 or later on Apple Silicon or Intel
- **Windows**: Windows 10 or 11 (64-bit)

[Blocked at first launch?](https://open-negative-initiative.com/download#verify)

![A snowy Paris street at night, a lit cafe under arcades, tyre tracks in the snow.](https://open-negative-initiative.com/media/carousel/snow-night-1400.webp)

***Snow night.** Kodak Gold, converted in Open Negative Initiative.*