Spot and Scratch Removal

[Chris Kern]

I've recently been scanning some old negatives from the 1930s.  Photoshop's automated "Dust and Scratches" filter occasionally is helpful, but mostly if I really want to clean up the surface imperfections I wind up doing it manually.  There must be some AI tools by now that work better than the Photoshop filter.  Any recommendations for a product that uses machine-learning for photo restoration?  Can anyone provide a link to a good comparison of various products from a reliable and disinterested reviewer?

[fdisilvestro]

Hi,

While not AI based, Silverfast has a plugin for Photoshop called SRDx - Smart removal of defects. It is not perfect (does not work well in high-frequency detail areas) but it works better than the Photoshop filter IMHO.

You can try it for free for 30 days www.picture-plugins.com/

[Chris Kern]

While not AI based, Silverfast has a plugin for Photoshop called SRDx - Smart removal of defects. It is not perfect (does not work well in high-frequency detail areas) but it works better than the Photoshop filter IMHO.[/url]

Yes, I tried it a while back and I agree: it's better than the Photoshop filter, but its primary benefit is in open areas—especially those that can be masked off—where spots and scratches are particularly apparent.  It's of limited value in areas with high-frequency detail.  It has been a while since I've used it, however, and probably I should check the current trial version of the plug-in.  Thanks.

My feeling is that if some company has been willing to go to the effort to create a good training set of images, reducing if not completely eliminating spots and scratches should be a tractable problem with current machine-learning techniques.  Of course there is a threshold economic issue of making the investment to create the training set, which no doubt is labor-intensive: you would need to collect enough original scans and their competently retouched counterparts for the neural network to "learn" how to differentiate between the source and destination images.  I know Microsoft has done some research in this area and even offers a product (MS-Windows only, alas), but I'm hoping someone knowledgeable with no stake in the outcome has reviewed the various alternatives for a post-processing (i.e., post-scan) workflow.

[drralph]

I too would like to see such a product.  But scanning negatives is not a growth industry, so there is little motivation to create a great new product.  As an aside, I notice that Ken Burns leaves an astonishing number of blemishes on his scanned photos that would be easy to fix.  He must value authenticity over aesthetics.

[langier]

Kodak once owned a company called "Applied Science Fiction" ASF, I think it was called. It may have had a stand alone version years ago to do the dust/scratch removal automatically but the best thing is that the software was incorporated into the Nikon CoolScans and I think the old Polaroid film scanners.

Originally it didn't work on Kodachorme because of the way the dyes were layered on the emulsion but I think in the latter version of the Nikon Coolscan line it had been tweaked to do so.

To make it work if I remember properly the film gets scanned for a forth channel using infrared light or filtration. Apparently this picks up the dust and scratches which can be subtracted out of the final scan. Voodoo magic for sure!

For some images, it's nice to leave the traces of its life as in the Ken Burns way. Having done a lot of manual clean-up I'm sure if he started to clean up the images, his films would be an hour long and every decade...

I think that both Silver Scan and Vuescan both have some clean-up features. However, the best way IMO still requires taking a close look at the image.

D&S filtering works great for skies and large flat areas and can be done with little thinking. Best to do this on a duplicate area and then mask this out to work on the areas with detail that one wishes to really clean up then do it manually at high mag.

By using layers to do the work, you can get the easy stuff done quickly and then spend the rest of the time in the areas that need the most careful work. It's not a cure for the problem, but it makes things a little easier/faster.