P: White Balance Eyedropper Tool No Longer Working Properly

[Todd Shaner]

The capability to use larger sample sizes with the White Balance Eyedropper tool was implemented in LR4:

http://feedback.photoshop.com/photosh...

This capability is no longer working properly in LR 5, 6, or CC 2015 and uses a fixed 5x5 pixel sample area regardless of 'Scale' or Zoom View settings. Please see the following test images for clarification. Tested with Windows 7 SP1.

[Todd Shaner]

UPDATE: It appears only the RGB values displayed in the eyedropper tool are incorrect. The applied WB correction uses the actual Scale setting sample area. See this post: https://forums.adobe.com/message/8929708#8929708

It still can cause confusion and should be corrected to show averaged RGB values for the actual Scale setting sample area.

[Bob Somrak]

Continuing our discussion from the above forum link, Steve indicated that the white balance tool only displays the value for ONE pixel where the eyedropper is at.  I created a photoshop white square with a single black pixel to test.  The wb tool displays the values for a 5X5 sample and not just a single pixel.  Unfortunately it also displays the 5X5 sample if the tool is set for 17x17.  At least is uses the 17x17 sample for setting the WB when it is clicked.  This should be considered a bug or at least a bad design.

[Todd Shaner]

That is what I'm seeing as well. The eyedropper tool RGB display values are calculated using a central fixed 5x5 pixel area regardless of the Scale setting, which extends to 17x17 pixels.

Here's another example that better illustrates the issue, with the WB eyedropper is set to maximum (17x17 pixels). The central cross-hair is placed on the corner of a 5x5 pixel black square (0, 0, 0 RGB) with a white background (100,100,100).

If the display reads only a single pixel then it should display 0,0,0.

If it is averaging over a 17x17 area then it should display (17x17) - (5x5) / (17x17) = 91.4, 91.4, 91.4.

[ssprengel]

Ok, you're right, the calculations from the above illustration would be:

So the result is a 5x5 average for the % both under the WB dropper area and under the histogram.

But the WB is still dependent on the full area, right?

And in the lower drawing in the first message, where it appears to be the central pixel is the value of the percentages, it is really that the zoom level of 1:2 is complicating things although it's unclear whether the zooming out is causing the eyedropper do use the non-zoomed pixels a couple out from the black so is in an all white 5x5 area at the original 1:1 zoom or something else, like using the central pixel is happening.

[Todd Shaner]

"So the result is a 5x5 average for the % both under the WB dropper area and under the histogram." Yes.

"But the WB is still dependent on the full area, right?" Yes.

What's ironic is that viewing my original posted screenshots it appears the central pixel RGB value is what's being displayed....just as you stated at the LR forum post. That was with LR CC 2015.3. I can't duplicate this behavior with LR CC 2015.6.1. So is this a bug or an engineering change implemented after LR CC 2015.3 (6.3)?

In my opinion a single pixel reading has no practical value as I stated in my original request here: https://feedback.photoshop.com/photoshop_family/topics/white_balance_eyedropper_tool_option

The WB eyedropper RGB values are useful when measuring different areas of an image for WB consistency or even for color matching portraits and product shots. Knowing "exactly" what area is actually being measured (i.e. averaged) is important. All that needs to be done to fix this is to display the averaged RGB value for the Scale setting being used.

[Rikk Flohr: Photography]

I tested a variety of scenarios using both Lightroom 4.4 and Lightroom CC2015.6.1. This is what I can report. 

Re. 5x5 Area for sampling: behavior hasn't changed on my system between Lightroom version 4.4 and CC2015.6.1.  The active white balance sample area for percentages shown is limited to a 5x5 grid.  The loupe was modified to show greater detail but does not affect sampled pixel percentage area size.

Re. Correct White Balance: Both Lightroom 4.4 and Lightroom CC2015.6.1 appear to be setting the WB sliders to the correct value.

Re. Incorrect RGB values shown: There is a difference in the RGB values shown for Lightroom 4.4 and Lightroom CC 2015.6.1.  A bug has been filed for this.

[ssprengel]

My testing contradicts your first point about the WB sample area always being a 5x5 grid.

The PERCENTAGES are always computed from the 5x5 grid.

The WHITEBALANCE is computed from the full grid whatever it is set to.

This is demonstrated by test images over on what turned out to be a hijacked thread about something else so the discussion continued over here on the feedback forum:

https://forums.adobe.com/thread/2053829

You can clearly see the sampled WB is warmer with the 5x5 and cooler with the 17x17 because the larger sample area includes some yellow.

Do you have any demonstration images to show your conclusion?  It's possible it works differently in different computers.

[Bob Somrak]

  Rikk Flohr wrote "The active white balance sample area is limited to a 5x5 grid.  The loupe was modified to show greater detail but does not affect sampled pixel area size."

I agree the sample area for the number display "in the tool" is a 5x5 grid no matter what size the grid is  but the WB set when you click is set from the 17X17 (or other) size grid.  You can easily test this by setting the tool to 5x5 and set the WB, do a CTRL-Z and then set the tool to 17x17 and set the WB.  (the tool is NOT moved}.  The WB numbers for the two sizes in the Develop Panel will be different if your sample area has a lot of changes. 
If this is by design it is very unintuitive.  Beings Lr is reading the pixels from the larger tool to set the WB it should be easy to reflect this is the numbers the WB tool is displaying when the size is changed.  

[Bob Somrak]

Thanks Steve

I just posted similar results a few seconds ago and concur with your findings on what area the WB tool is using to set the WB when you click.  This may not be considered a bug but it is an unintuitive design.

[ssprengel]

Exactly.

[ssprengel]

Exactly.

[Todd Shaner]

I agree. The WB correction applied to the Temp and Tint settings is correct and uses the the actual Scale setting area and not a fixed 5x5 area. Only the RGB numbers displayed in the eyedropper tool are calculated using a fixed 5x5 area. The displayed value should be calculated using all of the area selected by the Scale setting to avoid confusion.

[Rikk Flohr: Photography]

It sounds like you might want to request the "change in the sampling size area" as a new Idea. 

[Rikk Flohr: Photography]

So, if I understand correctly, aside from the incorrect RGB values shown (for which a bug is filed). The issue is that the WB Loupe, while applying the white balance as-expected, based upon the scale slider setting, is not modifying the percentages shown in the WB loupe?  This makes it more difficult to choose the area to click upon?

On the Mac OS (El Capitan) this behavior is still the same as it was in LR 4.4. It appears that this behavior has not changed. If you can demonstrate otherwise, I would need your OS version and the Lightroom version where the Loupe tool is using the greater than 5x5 area for calculating percentages so I can verify. Can either of you provide that? If we can show it is a regression in behavior, I can file it as a bug. Otherwise, we are looking at making more of a feature request to get the changes implemented. 

[ssprengel]

The inconsistency between the WB sample area and the percentages-sample-area seems wrong to me.  But perhaps this is as designed, and an explanation can be found, in some internal documentation or developer's memories.

The worst thing to me would be that you can't tell the sample area is 5x5 and it is easy to assume it is the full WB-sample area or the single central pixel.

Are the percentages there to show us how off the WB is before clicking, or only there to verify it's been neutralized after clicking?

Is there some uneven weighting of the pixels in the full WB-sample area giving priority to the central area or are the WB-source numbers a straight average.  If there is central weighting and the 5x5 is the main contribution then maybe it's less not ok that the 5x5 area is what the percentages are based on but still the inconsistency is bothersome.

[J453]

This issue should be addressed by today's update: http://blogs.adobe.com/lightroomjournal/2016/09/lightroom-cc-2015-7-now-available.html

[Bob Somrak]

Jeffery,


What exactly was changed?  It appears to work the same a it did before.

[Todd Shaner]

Jeffrey, nothing seems to have changed in LR CC 2015.7. The WB Eyedropper tool's display and the Histogram RGB readings still show a fixed 5x5 sample area, but when the Eyedropper is actually clicked it applies the WB using the selected Scale sample area (5x5 up to 17x17). This behavior is identical to LR CC 2015.6.1.

LR CC 2015.7
5x5 82.4, 82.4, 82.4 square on 82.4, 82.4, 65.4 background with a 17x17 Scale WB Eydropper centered on 5x5 square. Note the readings are 82.4, 82.4, 82.4 and not the "average" of the 17x17 mixed sample area.

[Bob Somrak]

Todd      Exactly what I am seeing.

[J453]

Good morning. We'd like to invite you to our prerelease if you're interested in evaluating a fix for this issue. Let us know and we'll get you added.

[Todd Shaner]

Yes, please sign me up.

[Todd Shaner]

Sorry for the delay–I've been on vacation with no access to a LR desktop. On my Windows 7 system the LR 6.12 Prerelease Update "fixes" the WB Eye dropper sample readings as follows:

1) The Eyedropper tool's RGB values  correctly show the "average value" for the selected sample size (5x5 through 17x17 Sample area) and NOT a fixed 5x5 sample reading. Good!

2) The Histogram RGB readings display the "average value" for a fixed 5x5 sample area. This is the same behavior as in LR 6.10. The Histogram's RGB values may differ from the Eyedropper tool's RGB readings .To avoid confusion it would be better if the Histogram displayed the same RGB readings as the WB Eyedropper.

3) The actual applied WB settings are correctly calculated using the Eyedropper Tool's sample area as selected in the Scale slider (5x5 through 17x17 selection). Good!

[Rikk Flohr: Photography]

Lightroom CC2015.12/6.12 was released today and should address this issue.  Please update your Lightroom to the latest version and let us know if you continue to see the issue. Thank you for your patience.

http://blogs.adobe.com/lightroomjournal/2017/07/lightroom-cc-2015-12-now-available.html

[Todd Shaner]

Rikk, LR CC 2015.12 on my Windows 7 system behaves as described in my last reply above. The WB Eyedropper issue appears to be resolved, but the Histogram readings still use a fixed 5x5 sample area. This is the same sample area used by the mouse cursor. Not a big deal since the WB is set correctly using the Scale setting sample area. It would just make it less confusing if the Histogram readings also matched the Eyedropper tool's readings.