From negatives to a photograph, in six steps

The app is Open Negative Initiative, a free download for the Mac. Every step below is one click or one drag.

1. Bring the files in

Drag your scans into the window. Nothing is copied, moved or modified.

2. Crop to the picture

Crop inside the image, so the film edge and the lightbox stay out of the frame. The histogram and the balances only count what you keep.

3. Check the mode

It already says Negative. Change it in the top bar only for slide film or black and white.

4. Press one automatic balance

Press AVG in the Color panel. If the colour looks off, try Mids. One undo takes it back.

5. Adjust two things

Exposure for brightness, Temperature for the colour of the light. Leave the rest for later.

6. Export

Select the frames, choose JPEG or TIFF and a colour space, and export.

If it does not look right

• Flat, milky or cyan on opening. Normal: nothing is placed yet. Press one balance.
• The colour is stubborn. Blue is the difficult channel. Look there first.
• One area stays mottled whatever you do. The scan clipped there. Rescan that frame a little brighter.
• The whole roll needs it. Select the roll and press one balance: each frame is measured on its own.

Curious why it works? Density inversion is the idea, and the list of what the app does is the map.