P: Averaged white balance reading with White Balance Selector

[FeedbackCommunityMember]

I will often click on a gray card with the White Balance Selector to white balance an image. However, if I click on that same gray card multiple times I will get a slightly different result each time, as if it's giving me a reading on a single pixel on the gray card rather than an area. As a parallel in Photoshop, it's like using the "1x1 average" with the eye dropper.

Perhaps it might be nice to give the option of a 3x3 or 5x5 average, or perhaps you could drag the eyedropper over a gray card and it would sample several times over that area.

I figured that an averaged white balance would give a better result rather than a single pixel's white balance.

-Bruce!

[Rikk Flohr: Personal]

White balance in Lightroom is averaged over a 5x5 pixel area. There is no option to change it currently.

[Lee Jay]

Are you sure about this Rikk? I thought it was 5x5 at whatever your view size is, so zooming out makes it cover a wider range. No?

[Rikk Flohr: Personal]

Pretty sure. see this thread: http://www.lightroomforums.net/showth...

Loupe changes the precision with which you may view the selection but not the sample area.

[Lee Jay]

I can't see that thread, but I'm reasonably sure that I'm correct about this - zooming out will get you a wider averaging area with the WB picker. Changing the size of the grid will not.

[Rikk Flohr: Personal]

Unless there has been an undocumented change in the code since July of 2010, this is not the case. We constructed test graphics and verified this at that time. i didn't realize the link was restricted. Essentially we constructed a test graphic with a 5x5 white pixel trap and tested it at various loupe levels.

I will discuss with the team today and see if I can get clarification.

[Mark Sirota]

My recollection matches Lee Jay's -- zooming out increases the sample area. I haven't tested recently.

[Rikk Flohr: Personal]

Tested today and verified with the team. 5x5 pixels. Mark, I know you can access the thread mentioned above as you were part of the discussion last July at LRForums

[Lee Jay]

Turns out we're both right, but you're right for Lightroom (5x5 always). Possible future enhancement.

[Rikk Flohr: Personal]

I like it when everyone is right.

[Mark Sirota]

I can prove that Lightroom's white balance dropper is sensitive to zoom level:

Create a file with a 5x5 gold square in the middle surrounded by blue. Import into LR, press W, click the WB dropper in the middle of the square at 1:1 and 1:4; you'll get different results. (I'd attach a test file, but it needs to be TIFF to work in LR, and this forum doesn't allow TIFFs. I can mail it to you if you're interested.)

[Rikk Flohr: Personal]

After working with Mark's test files which he emailed to me, I suspect what is happening is that at views 1:2, 1:3, 1:4 that Lightroom is measuring White Balance from the resampled preview rather than the original Raw file. We are currently working to confirm this with the team.

[Geoff the kiwi]

The answer is that the 5x5 is screen pixels rather than image pixels so will vary with zoom ratio.

[Rikk Flohr: Personal]

LR4 has changed White Balance sampling behavior.
http://blogs.adobe.com/lightroomjourn...

[Arne Rudi]

Improve the white balance eyedropper by making it possible to use the average of several pixels for WB instead of sampling one individual pixel. Currently, due to color noise in images, the WB eyedropper is sensitive to the exact pixel being sampled. Move the eyedropper just one pixel up or down and you will get a different WB. 

Would be excellent if it was possible to draw out a rectangle when using the WB eyedropper and use the average of the pixels within the selection for WB.