ART 1.18.1 and dust spots

Is there an easy way of viewing the dust spots in an image with 1.18.1?


I’m not sure I understand the question, sorry. If you are looking for a method to detect possible dust spots automatically, I’m afraid there’s nothing like that in ART though.


Use the local adjustment Texture tool, turned up to the max. It’ll emphasize the spots and you can find them more easily. Just turn it off otherwise, it’s pretty extreme. :slightly_smiling_face:

I was looking for something that would show me where the dust/spots are.

Something like in Lightroom, turn the screen to black and show the edges of the dust/dirt, then I could go and clone them out.


I just tried and it doesn’t show me the dirt. Am I missing anything?


Apparently it’s more or less useful depending on the background. You might need to tweak the intensity to see the dust spots against a highly textured background. For example, here’s a sky from a Play Raw image, before and after:

I guess the important thing is to find some way to accentuate the slight contrast difference of the dust spot and / or its edge. Maybe another tool might do that. Or if there’s some way to find circular low-contrast features… but I don’t know of anything like that in ART.

Maybe an alternate strategy might be to do this in an editor that supports layers? You could probably use an extreme USM layer to expose the spots, then use that layer mostly transparent as a guide to find and clone them out.

I seem to remember seeing a video by @Andy_Astbury1 show the use of a curve in RT that could be used to located dust spots. Just can’t remember which video it was.

Yeah, the trick is you need to emphasize a certain type of low-contrast feature without emphasizing anything else. If there was a way to detect only perfect circles, that would be a huge gain.

That might be a good question to ask of the G’MIC folks. If there’s a way to even somewhat isolate and enhance dust spots, maybe a reference guide image could be made with (only) dust spots emphasized. I played a bit with G’MIC but I’m pretty hopeless and came up with nothing useful so far.

Hello, I’m experimenting with some kind of auto dust removal on scanned negatives, using a parametric mask to isolate white spots.

It certainly isn’t a perfect method, but it can help to do a first cleaning. This is a recent scan from a negative taken some 25 years ago.


Set parametric mask like so:


Show resulting mask:


For further cleaning I often use the brush mask in the softening tool, works especially well to clean up dust spots in the sky. Works faster than the Spot removal tool in ART, for me at least.

Nahh…that was in Photoshop me old china!

Based on Andy’s and GIMP’s method I created a spot detection method for RawTherapee way back when.

I just tested these rtc files using ART and they work on that platform too.

That is one dusty sensor :smile:

Depending on the image you do need multiple methods to be able to detect the spots, hence the 4 I created.

Here are the 4 spot detectors in zip format.

Good thing that both RawTherapee and ART have the ability to set 2 Tone Curves…

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I have seen this one presented as a curve to try to show them…