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Mark Sirota
Known Participant
August 21, 2024
Answered

Is this the expected behavior of the Whites slider?

  • August 21, 2024
  • 1 reply
  • 1543 views

I've just discovered that the Whites slider doesn't behave the way I have always thought it behaved, and as an LR user since 2006, and a frequent user of Whites since it was introduced, I'm wondering whether it has always been this way and whether this is the intended behavior.

 

Here's a short timelapse video illustrating the problem. Note how the sky is suddenly darker in a few frames. Note also that the darker frames are the ones with light in the foreground (which is caused primarily by people in the foreground using red flashlights).


These were shot on a Nikon D850 using the built-in intervalometer (13 second exposure every 15 seconds), in manual mode (and manual everything) with Active D-Lighting disabled. They were then all processed identically in Lightroom Classic (using manual adjustments, no auto anything). The video was then created using the Slideshow module.

I have confirmed that they're all identical (and that Active D-Lighting is disabled) by carefully comparing the EXIF data of all 380 frames. I confirmed that they were processed identically by resetting them all, then processing them together using Auto Sync.

After some investigation, it turns out that the culprit is the Whites slider. They all have Whites +60 (and exposure +1.00). In the frames with significant light in the foreground, the Whites slider doesn't brighten the sky as much. The Exposure slider doesn't seem to be affected by the brightness of the foreground.

 

So my question is, is this the expected behavior of the Whites slider? I would have thought it would affect equivalent pixels equally, regardless of what's happening in another part of the frame. I tried older process versions and found the same behavior (going back to PV3 when Whites was first introduced), but I'm amazed I've never noticed this before.


For those willing to dig in, here's a Google Drive folder containing the video, two adjacent raw files, and the output of exiftool for each of those raw files:
https://drive.google.com/drive/folders/18ZJFC6o2zQ1eOkP0gIBLdS_9jwHd5KXn?usp=sharing

 

Thanks for any insight!

This topic has been closed for replies.
Correct answer richardplondon

A number of adjustments since 2012 updates (or so) have become image content adaptive, some more powerfully than others. With early PVs only IIRC Clarity and Fill Light and Recovery were. In current PV you can strategically do some of the tonal shaping using Tone Curve instead. That acts like an overlaying filter applying the same standard relative change onto a certain pixel value wherever found in images, regardless of whether relatively lighter or darker tones may occur near to instances of that value within each photo. Tone Curve operates secondarily onto whatever range between picture-white and picture-black the other adjustments are creating. Tone Curve has no direct access to the original image data and thus cannot play any part in controlling highlight recovery and such. IOW it can dor example (nondestructively of course) further clip, but cannot itself act to reverse any clipping. So use of the Basic Panel etc cannot be eliminated.

 

That said, by including Exposure and Contrast in the Basic panel to do the heavier work and then reserving Shadows / Highlights / Whites / Blacks for tweaks at consequently weaker strength, a lot of the more obvious image-adaptive behaviour can IME be suppressed below the level of  noticeability.

1 reply

R
Community Expert
richardplondonCommunity ExpertCorrect answer
Community Expert
August 21, 2024

A number of adjustments since 2012 updates (or so) have become image content adaptive, some more powerfully than others. With early PVs only IIRC Clarity and Fill Light and Recovery were. In current PV you can strategically do some of the tonal shaping using Tone Curve instead. That acts like an overlaying filter applying the same standard relative change onto a certain pixel value wherever found in images, regardless of whether relatively lighter or darker tones may occur near to instances of that value within each photo. Tone Curve operates secondarily onto whatever range between picture-white and picture-black the other adjustments are creating. Tone Curve has no direct access to the original image data and thus cannot play any part in controlling highlight recovery and such. IOW it can dor example (nondestructively of course) further clip, but cannot itself act to reverse any clipping. So use of the Basic Panel etc cannot be eliminated.

 

That said, by including Exposure and Contrast in the Basic panel to do the heavier work and then reserving Shadows / Highlights / Whites / Blacks for tweaks at consequently weaker strength, a lot of the more obvious image-adaptive behaviour can IME be suppressed below the level of  noticeability.

    M
    Mark SirotaAuthor
    Known Participant
    August 22, 2024

    Thanks Richard, that's very helpful. Further experimentation reveals that with significant enough strength, at least the Exposure, Contrast, and Whites sliders exhibit this behavior, so it appears that when consistency is important (such as for a timelapse), the tone curve is the way to go unless more moderate use of the basic sliders is sufficient.

    Conrad_C
    Community Expert
    Conrad_CCommunity Expert
    Community Expert
    August 22, 2024

    That conclusion is absolutely true and confirmed by the author of LRTimelapse software. He’s got a great video (linked below) explaining how this happens. He discusses which options are image-adaptive (wonderful for single frames, not so consistent for time lapses) and which options are applied the same way to every frame regardless of content (ideal for time lapses). The last 10 minutes of the video are especially enlightening (no pun intended), where he specifically tests each option adjusted in isolation in a time lapse to show you how much you might want to use or avoid that option. And, he shows how the inconsistent results are amplified if the images use an Adobe raw profile; to mimimize the problems apply a camera matching profile instead.

     

    It’s not that you can’t use the image-adaptive options at all with a time-lapse, they are still useful for times when the linear options aren’t enough to solve a problem. But you’ll get the most consistent results among time-lapse frames if you use the image-adaptive controls as minimally as possible, and leave the heavy lifting to the more linear options like the Tone Curve.

     

    Sometimes it’s difficult to understand what the change was between frames that caused a different result, but it can be as subtle as a transient reflection on a hill of a passing car’s headlight, or a traffic signal changing. And as he shows, it could be a changed area that you aren’t aware of because it’s outside the crop area!

     

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