ART 1.21.3 & green blob

I have a big green blob appear on the center of the image when I’m in Zoom 1:1

No blob in F: fit

blob in Z 1:1

The file is an OM-1 mk2 ORF. I have a whole bunch of photos. Doesn’t happen with the other images. Same camera, same lens, same aperture.


This is about 15mn after posting the 1st one. I cleared the processing processing profile and now the green blob does not appear.

What happened or didn’t happen?


Really hard to say without a crystal ball… :thinking:
More seriously, without knowing what steps you performed I have no clue, sorry

Do masks for 1 : 1 modules only show at 100 percent?? Seems like a perfect circle?? No idea and no access to ART right now so this might be a stupid idea…

I performed no step. I have a new lens and was looking for more than 1:1. Usually, I’m not a pixel peeper but I wanted to check is the lens is decentered or what else could be wrong.

File browser > double click > Z for 1:1 then I saw the “green blob”

It was only this single image. I should have kept the ARP, but it doesn’t happen anymore after:

File browser > right click > processing profile operations > clear


Understood. Let me know if it happens again

Greetings- first post and thank you for ART.

I bet I can help on this because I saw it yesterday and reproduced it just now in ART 1.22 on Windows 11.

On at least one raw file from my Olympus E-M10 Mark II, if I use embedded lens corrections and enable chromatic aberation correction, the green circle appears. If I disable the CA correction, the circle disappears. The circle doesn’t appear when I use “Automatic from database” lens correction or manual selection lens correction.

I have attached a raw file that exhibits the behavior, and a profile that allows you to just toggle that on and off. I agree to release the photo rights.
MX220401.ORF.arp (12.6 KB)

MX220401.ORF (13.4 MB)

I was delighted to see that ART can deal with the embedded olympus lens corrections in the raw files. I don’t think any of the other common open source raw developers do.

Also supported in darktable since the last 4.6 release.


The code in ART is in fact stolen from darktable, and chances are that I introduced some bug in the porting… I’ll take a look when time permits. Thanks

I was curious if it was just something with that particular lens or body that I used in the file above (Lumix 12-60 on E-M10m2) but found the green circle also appears in a photo I shot with E-M1m2 and Olympus 12-60 SWD (four thirds). So it doesn’t seem to be the body and/or lens specifically.

This maybe should spin off to a different topic but in looking at this issue I noticed a couple of things about embedded profiles…

My three four thirds lenses (12-60, 55-200, 14-54) only seem to embed CA corrections according to ACR. The Lumix 12-60 has CA and Geometric corrections embedded. I’m willing to believe that in the early 00’s, it wasn’t possible to do Geometric corrections in-camera so the lenses didn’t have that information transmitted.

I found some shots from my Fujifilm X-T10 and the XC 16-50 lens. ART auto matches that lens to the database and has no embedded corrections as an option.

ACR shows my Fuji XC 16-50 has CA, geometric and vignetting corrections embedded. I wonder if ACR has it embedded in itself and not actually the raw file since it seems to know about Fujifilm cameras and lenses without having separate profile files.

Lens correction data is saved in Raw file as metadata. And ART can read only some manufacturer’s (only Olympus / OM system?) metadata, because the format of lens correction metadata varies by manufacturer. If software developers want to get the metadata information from manufacturer, nondisclosure agreement with manufacturer is needed and FOSS developers cannot use these information. Only some metadata format which were hacked by volunteers are usable for FOSS.

I tried it quickly in darktable, and saw no problem there. At the same time, let me thank you for ART here, Alberto. Although I’m a darktable user, I do run ART (and RawTherapee, and filmulator…) from time to time, and it’s a great tool, results are impressive out of the box! So keep ‘stealing’ :slight_smile:

Also sony, Fujifilm, and dng

do you have a sample image with visible CA? I think I fixed the problem but I’d like to test it before declaring success…

That means if we convert a raw file that ART cannot read metadata to a dng file, then ART can read the metadata?

If the dng conversion also converts the metadata, then I suppose so. But I don’t know whether that is the case.

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You mean “shared lovingly because we appreciate each other” :heart_eyes:


Thank you. I will try it later.

2024年6月5日(水) 23:09 Alberto via <>:

ART 1.22 on Leap 15.5

Up to now, the green blob was only on the screen during the editing process but it wasn’t on the exported image. Now the green blob (grey since I converted to b&w) also shows up on the exported images.

Here’s the file:

Here’s the arp

here’s a exported jpg

here are the screenshots

I don’t know what changed but up to now, the blob was only in ART, now it’s also on the exported jpgs. Is there a way of not having the blob in the exported jpgs?


The green circle was on the exported version for me before…