P: Denoise - Color shift from the original to the Denoise version (Fuji X-T4)

[XenonDeathFlash]

Issue: AI Denoise - Magenta/Purple shift on resulting DNG

Camera Raw version: 16.2.1.1767

OS and version: Windows 10 Pro (10.0.19045)

Steps to reproduce the behavior:

1. Open the attached example photo in Camera Raw

2. Use AI denoise with any setting

Expected result: Camera Raw / Ai denoise should produce a DNG with colours being the same as the original photo.

Actual result: Camera Raw / AI denoise produces a DNG with colours shifted towards magenta.

Example from a DPReview gallery:

Unfortunately I can't attach the raw used because I get an error "The attachment's dsf4199.raf content type (image/RAF) does not match its file extension and has been removed." but here's a link to the gallery:

https://www.dpreview.com/sample-galleries/2665176873/fujifilm-23mm-f1-4-lm-wr-pre-production-sample-...

[XenonDeathFlash]

I created a post on the DPReview forums before this bug report:

https://www.dpreview.com/forums/thread/4755558#forum-post-67643436

Another user there has confirmed that they also get the magenta cast on the example photo.

[XenonDeathFlash]

Bump.

[XenonDeathFlash]

Also:

The issue doesn't happen only on the example photo obviously, it's just a good example of the issue. I've noticed it on a lot of my own photos but it's not consistent and sometimes it's more subtle.

[Rikk Flohr: Photography]

Thank you for the link to the sample file.
I have forwarded this to the Camera Raw team for review. 

I've modified your title, as the shift appears only in the blue channel on the provided image rather than in the magenta zone. I think the flesh-tone appearance shift gives the impression of magenta while interrogating a point indicates that only the blue channel is moving. 

Update: 

The minute blue shift in this particular image is amplified by its proximity to the low end of the White Balance scale ~2150° K.  A small nudge of the Temperature slider should correct for this. I would expect similar behavior from images where you approach the limit of the WB range. 

[XenonDeathFlash]

Hi Rikk!

Thanks for passing it on!

I should add that even though the photo i linked to is from an X-T4 I've seen a similar shift happen in my own photos from an X-T2. Can't really show those though they are mostly personal family photos.

[XenonDeathFlash]

Re: Your update about WB

Playing around with WB still doesn't get you the colours from the original. You'd have to play around with the Calibration and HSL tool to remediate the issue. 

[XenonDeathFlash]

@Rikk Flohr: Photography 

Any updates in regards to this issue?

[XenonDeathFlash]

Just an update; this issue is still not fixed and just adjusting the WB doesn't solve the issue.

I'm seeing this magenta shift happen quite often with my own RAW files, so much so that I can't just run AI Denoise on higher ISO shoots and trust that the colors are good anymore. 

Here's another DPReview example:

https://www.dpreview.com/sample-galleries/4783322917/fujifilm-x-h2-review-samples/9603333339

[XenonDeathFlash]

Here's an Adobe forum post where a user has the same issue with his X100V files. 

https://community.adobe.com/t5/lightroom-ecosystem-cloud-based-discussions/ai-noise-reduction-in-lig...

[andrezou]

Here is the first picture again, but I screenshot the TIFF file instead. The green color is much more noticeble here.