As anyone who's ever tried to process an underwater photo knows, backscatter removal is frequently an incredibly tedious process. While you can sometimes speed things up with shortcuts like the dust and scratches filter in Photoshop, it can still require you to carefully paint masks when you have backscatter in textured areas. For example, consider this photo of a pair of reef manta rays from the German Channel in Palau. This was my first ever attempt to photograph mantas, so I botched the shot by forgetting to turn off my strobes, resulting in me lighting up every speck of backscatter in the ocean. While it'd be relatively easy to remove most of the backscatter in the bottom half of the frame with the dust and scratches filter, it would be difficult to do the same with all the backscatter covering the textured surface of the water without carefully painting over every speck, at which point it's not really any faster than using one of the spot healing or clone tools instead.

 

 

However, I just discovered a piece of software called Retouch4Me Dust (https://retouch4.me/dust) that is designed for removing dust particles from product and portrait photography. To use it, you would go `Filter > Retouch4me > Retouch4me Dust` and select from one of 3 AI models: "coarse dirt", "medium dirt", and "fine dirt"; these are each optimized for different sizes of particulates. Here are the default results from each model on this image:

 

Coarse dirt:

 

 Medium dirt:

 

Fine dirt:

 

As the backscatter in this particular image exhibits significant variation in size, I found that the results were better if I applied all 3 models in succession:

 

Retouch4Me erroneously removed some of the patterning on the lower manta and darkened the space between the cephalic fins of the upper manta, but that can be easily resolved by applying a layer mask to preserve the markings:

 

There are still a few remaining spots here and there, as well as cases where Retouch4Me only darkened a spot but still left a little grey patch behind, but overall I think the software did a pretty good job on this image with minimal effort on my part. The listed price is $124, but I found that you can save 20% by searching for affiliate links in sponsored YouTube reviews and the like. I've only tested it on this one photo so far and may end up looking like an idiot if Adobe decides to add their own AI dust removal at some point, but for now I'm pretty happy with my purchase.

Did you test how the software effects detail/resolution in the photos?

(Some 100% crops of a photo, very well in focus and with a lot of details, before and after the different treatments would be very helpful)

 

Wolfgang

2 hours ago, Architeuthis said:

Did you test how the software effects detail/resolution in the photos?

(Some 100% crops of a photo, very well in focus and with a lot of details, before and after the different treatments would be very helpful)

 

Wolfgang

 

Here's an example of a shot of a giant moray (and not quite in focus bluestreak cleaner wrasse) taken at a much closer distance:

 

This is what it looks like after applying all 3 filters again (though I think just the medium dirt filter probably would've been enough on this one). As you can see even without zooming in, the software incorrectly removed some false positives, such as the white around the pupil and some of the natural patterning on the moray:

 

Here are before and after crops of the top part of the moray. Sharpness and detail has generally remained unchanged, but as mentioned before, some of the moray's spots were lightened and the white ring around the pupil was removed erroneously:

 

It seems to do a better job when it comes to removing backscatter from out-of-focus areas, like in the before and after of the top left portion of the image:

 

If I was editing this photo seriously, I'd probably try to use a layer mask that selects the background + the lighter parts of the moray using some sort of luminosity mask to preserve the moray's spots, and then also paint the pupil ring back in (or at least, I would if I knew how to create a luminosity mask in Photoshop...)

Edited April 22, 20241 yr by Kamaros

Surprisingly good results!

There is a dust and scratch filter in photoshop however needs to be used sparingly as it softens the image 

when the backscatter is on the subject removing the individual spots is always better

 

7 hours ago, Interceptor121 said:

There is a dust and scratch filter in photoshop however needs to be used sparingly as it softens the image 

when the backscatter is on the subject removing the individual spots is always better

 

Yes, I find the dust and scratches filter is generally a good solution for open water backgrounds, but doesn't work very well for backscatter sitting on top of any surfaces with details you'd like to preserve since it tends to blur everything underneath as well. The reason I was excited to discover Retouch4Me Dust was that it does a better job at leaving underlying details untouched. I think it's still best paired with some masking to prevent false positives from being removed, as well as some additional spot removal for any backscatter it failed to identify, but overall it seems a lot faster than the alternative for certain shots.