The best color negative inversion method
How to use
1. Preparations
Adobe Photoshop or Affinity Photo required. How to install and use actions.
Best results are achieved with linear scans saved as 16bit RGB .tif files. Check out this guide linear raw scan tif.
Try to leave around 2-10% of room around the actual scanned frame, for colour sampling of the negative film base.
You must ensure that the scan doesn't have missing/clipped data, caused by inadequate scanner exposure.
2. Base sampling
For the action to work, we have to first sample the color of the negative base.
This can be done either from a separate frame, or from leaving a bit of base visible outside of the scan crop.
Once the base is sampled as the foreground color in Photoshop, the action can be used on all scans from the same batch, but the scans have to share the same settings. For best accuracy, use a 5x5 pixel sample size on your Eyedropper Tool, and ensure that the sampled coluor is the lightest tone in your uninverted scan.
2. Base sampling without base outside of the frame
Sometimes your scans might not have any negative base visible outside of the actual photo frame, and maybe you can no longer redo the scan.
Thankfully there is a way around that
Take a look at this video, explaining the process.