Image tone changes from Lightroom to Photoshop

Forum|Forum|10 months ago
May 7, 2025
2 replies
4616 views

Hi there, this is quite an embarassing problem, and I cannot find the solution.

If I process an image in Lightroom Classic, and edit it in Photoshop, the copy that has opened in Photoshop has different tones.

I am using the Adobe RGB colour space in Photoshop, and Lightroom's External Editing colour space preference is set to Adobe RGB, and Bit Depth is at 16bit.

I am using Photoshop 26.6, Lightroom Classic 14.3, and Camera Raw 17.3. The computer is a Mac Studio M2 Pro, Sonoma 14.4.1.

Attached are files showing the difference between the LR and PS images, plus the relevant LR and PS settings.

Please help! I have alway been winging it with colour space and profiles, but this one has me beat.

Thanks, Jamie

macOS

D Fosse

Community Expert

This is an issue that has been reported from several Mac users lately. The symptom seems to be the same: excessive black clipping in Lightroom compared to Photoshop.

I would start by determining which of these two is the correct representation. That's pretty easy to determine. Take screenshots of both, assign your monitor profile, and convert back to Adobe RGB. All the 3 histograms - original Adobe RGB file and the two screenshots - should now be a perfect match. If they're not, the odd one out doesn't display the file correctly.

So far, all the signs point to a bug in MacOS - specifically, the GPU driver component in MacOS. It could be an Adobe bug, but if so, it's specific to the Mac Photoshop version. This has never been reported from Windows, and cannot be reproduced by Windows users who have tried (including myself).

And if, as you say, disabling the GPU clears it, that's further confirmation.

Jamie FarquharsonAuthor

Known Participant

Good Morning D,

I have started the diagnosis process as you detailed above, but have to confess, I have got a bit lost. Here is where I am:

Take screenshots of both,

Screenshot taken from LR, with GPU on.

Screenshot of same image, taken from PS. Conversion Engine is Adobe ACE in colour settings.

Are these screenshots taken under the right conditions for this test?

assign your monitor profile,

Problem here- Both screenshots are using the monitor profile by default so I cannot re-assign the monitor profile. Where have I gone wrong?

and convert back to Adobe RGB. All the 3 histograms - original Adobe RGB file and the two screenshots - should now be a perfect match. If they're not, the odd one out doesn't display the file correctly.

I have trouble working out where I get the original RGB file from. Is it simply the same image used for the screenshots opened from LR into PS, or am I hopelesly off base?

Sorry for asking for clarification, in my opinion you have already gone above and beyond with this. I feel like I'm really close to grasping it, and I just need a couple of pointers to complete the process. I'm really looking forward to getting to the bottom of it, and hilst it's nicer to have closer matching images now, as you said in your reply last night, both colour management engines should be producing the identical result, and we want to know why they aren't.

Best regards,

Jamie

D Fosse

Community Expert

That's great, thankyou! I first saw your message as an email, and carried out your instructions from that. I missed your edit about using a low ISO image. My test image has an ISO 0f 1000, but I think the principle still stands.

Having been through the process, it's the LR histogram that is the odd one out. Attached are the images with the histogram. I'm not sure if it will be possible to see the difference in this forums viewer, it's very indistinct in my original post, but the histograms make it clear.

Also, the attached file "LrScreenshot-NoGPU" is a screenshot of LR with GPU switched off and then put through your process. It's closer to PsScreenshot and _DSC3458-P than LrScreenshot, but still not precisely the same. As a temporary work around it will do, but what would you suggest the next step is?

Thanks again for your time,

Jamie

OK. Yeah, I just repeated the exercise myself, and I discovered that noise needs to be eliminated unless you have a small file that can be displayed in full at 100%. Excessive noise adds a lot of dark values that disappear when downsampled. The noise influences the "original" histogram, but not the two "screen" histograms because they are already downsampled, killing the noise.

One way to get around this is to downsample the original RGB file before screenshotting the histogram, so that it fits the screen at 100%. That gets rid of the noise, the same way as for the other two image screenshots. In other words, this levels out the playing field.

Here's what I got (see the file names):

As you can see, Photoshop is pretty dead accurate. Lightroom (displaying the raw file) is ever so slightly off in the far darkest values, but there's no way I'm able to see that difference using Eizo coloredge monitors. For all practical purposes, these are identical.

Note that this measures the accuracy of the GPU/color management and your monitor profile combined. I don't know of any way to separate these two components. So if you don't get a match, rerun your monitor profiling first.