Question: Does anyone understand the .acr file that appears to be produced by Camera Raw in v14.0?

[DonH]

Since updating to PS v23.0 and Camera Raw v14.0, it appears that Camera Raw now outputs a second sidcar file - in addition to <filename base>.xmp, I now see <filename base>.acr.

I once negelected to move this file along with the raw file and xmp file.  When I opened the image again in Camera Raw in the new directory, Camera Raw indicated that the select subject mask was not available and had to be re-run.  After re-running the mask it appears to be fine.

Does this .acr file contain information related to the new masks, and, if it is misplaced, can it be reconstructed witout loss of information by rerunning the masks in ACR?  I suspect the same situation could occur if a file is edited in ACR, then moved and imported into Lightroom without the .acr sidecar.  I've not tried it importing edited files (with our without the .acr sidecar) into LR (Classic) yet.

Environment:  MacOS Catalina and Nikon .NEF files, but I doubt this situation is OS or RAW file dependent.

I haven't been able to find any information on this at all.

Thanks,
Don

[Lumigraphics · Accepted solution]

The .acr files store the new masking data introduced in ACR 14. XMP sidecar files are text but the .acr file is binary. They must all be moved together.

[DonH]

Thank you!

[contributor129038]

They are sidecar ai-generated selection masking data. If you used "select sky" and "select subject" and disabled the "embed xmp in DNG" option, they appear. I think the continuous process of updating the selection functions generated with "artificial intelligence" will be stored in these files to reload them quickly instead of recalculating them every time.  (Oct 2022) there are two (sky, subject) so far.

[rickburress]

In Camera RAW v. 15.1, the .acr files do not get embedded, even with the setting turned on (“embed .xmp in DNG”) when editing a .jpg file. It seems to work as expected with both .dng & .tif.

(And, of course, there are now even more available masks than the 14.x “sky, & subject.”)