Looking for a Mac way to straighten and auto-crop scanned images

June 24, 2024 3:53 PM

I scanned hundreds of old film negatives. I'm looking for an easy way to get them 100% straightened, and crop off the black/white, non-image edges. Looking for some automated/AI way to make this happen using a Mac.

I have recently scanned hundreds of 35mm film negative images using a Plustek OpticFilm 8100 scanner negative scanner.

The little tray that you scan the negative strips in... it didn't always click in to the exact perfect position, so you had to do a preview, and while the preview scan was happening, jiggle the tray until you could see from the preview image that the strip was in the correct position, and then you could do a normal scan.

This led to most of the scanned images being a tiny bit skewed clockwise/counter-clockwise.

In addition, the scans include a white border (or sometimes black) around edge of the photo where it either scanned the edge of the plastic tray or the non-image part of the negative.

At first (because each scanned image took about 8 minutes to scan), I would try to rotate and crop the images as I went, but that became too much juggling between computers, so I gave up and just focused on "scan now, crop later".

I have dozens of folders, each with 36–150 scans, each of which I would like to have straightened and cropped.

I was thinking that, in this age of new AI tools, surely there must be a Mac app out there that has this ability, but so far I have only seen apps that do things like separate four photos that were scanned together on a flatbed scanner.

Any one know of any Mac apps, or Pixelmator Pro/Photomator plugins that would let me accomplish what I want to do?

I've put an example of one of the scans here.

posted by blueberry to Computers & Internet (3 answers total)

Please take a look at GraphicConverter.

I don't know if it uses AI, but it has long had ways to straighten and auto-crop, and can do those things to a folder full of images.

It's shareware, so you can try it out before paying for it. (However, if you like it and use it, I encourage paying for it; it's great software and the author provides great support.)
posted by kristi at 4:23 PM on June 24 [3 favorites]

I'm pretty sure that Graphic Converter cannot straighten automatically, but it does let you create workflows and apply them to a bunch of images as a batch. It also has a nice manual-straightening feature where you draw a line following a major vertical or horizontal feature in your image and it uses that as a reference for straightening. It's a great app.

There's another app, Retrobatch, and it is dedicated program for creating image-manipulation workflows and applying them to images (particularly in batches). It does have a straightening "node" (that's what its workflow steps are called), "Auto Level."
posted by adamrice at 7:50 AM on June 25 [1 favorite]

Response by poster: So far, the closest* I've found is using the Photomator app thusly:

1. import images into Photomator
2. select the images to process
3. hold Control and select Workflows > More Workflows… from the contextual menu
4. in the resulting Workflows window, tap the + icon to create a new template
5. select Rotate and Straighten
6. change ratio from Freeform to 2:3 (for portrait format photos) or to 3:2 (for landscape format photos)
7. select Crop and ML Crop, as well as Preserve Edits
8. click Apply to process the images

* (on four test images, the above Photomator workflow seemed to straighten and crop the images almost perfectly, but one image still had a pixel-wide white line along the top that I would need to crop manually)
posted by blueberry at 5:13 PM on June 27