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Click *What* to Set WB in ACR?

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kirbysdl

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I thought that when using the white balance eyedropper tool in Adobe Camera Raw, all you had to do was click a neutral (gray or white) area and ACR magic would take care of most of the rest. However, in this tutorial, Russell Brown says that you specifically cannot measure against a 18% gray card. Why would that be?! In other tutorials, I've seen plenty of people using this tool to click a white or gray area to set WB, so I'm confused...

Link to tutorial: http://www.adobe.com/digitalimag/tips/phs7rbrawbasics/index.html

Can anyone shed some light on what he's saying? Is he misinformed, or am I misinterpreting his recommendation as different than others'? Perhaps he was talking about an older version of ACR that behaves differently? Thanks!
 
He explains that it is a "White Balance Tool and not a Grey Balance Tool like you would find when using Adobe Levels".
kirbysdl said:
I thought that when using the white balance eyedropper tool in
Adobe Camera Raw, all you had to do was click a neutral (gray or
white) area and ACR magic would take care of most of the rest.
However, in this tutorial, Russell Brown says that you specifically
cannot measure against a 18% gray card. Why would that be?! In
other tutorials, I've seen plenty of people using this tool to
click a white or gray area to set WB, so I'm confused...

Link to tutorial:
http://www.adobe.com/digitalimag/tips/phs7rbrawbasics/index.html

Can anyone shed some light on what he's saying? Is he misinformed,
or am I misinterpreting his recommendation as different than
others'? Perhaps he was talking about an older version of ACR that
behaves differently? Thanks!
Click to expand...
 
This video is the older version of ACR for Photoshop 7. However, in CS2 ACR, I find that using the tool on a neutral gray seems to work just fine. Even clicking on a black speaker grill cover seems to work well. I actually had more trial and error sampling the "white" areas of my calico cat's fur. Anyway, it is only a quick approximation and may require sampling different areas before you are satisfied. I would still make final adjustments with PS adjustments.

--
My 2¢ worth
My still camera 'evolution' 1950-present:
http://www.pbase.com/filer/image/49099880/original

Joe Filer
Mahomet, IL
http://www.pbase.com/filer
 
Gale Bizet said:
Suggest you watch and listen carefully to him.
Watch a couple times if necessary.
Click to expand...
What a non-answer. I did in fact watch several times but still didn't understand. Read my restating of the problem below, which may be more clear than my original statement.
cspringer said:
He explains that it is a "White Balance Tool and not a Grey Balance
Tool like you would find when using Adobe Levels".
Click to expand...
Yeah, I got that, but he describes using a color tone chart, and clicking on the colored patches (presumably not the gray/white patches or else a gray card would have sufficed) to set the white balance. Specifically, he says "off-white three-quarter tone." While many other tutorials say to click on an area that should be white or gray, he specifically says no gray (e.g. a gray card).

In the end, he ends up clicking on the mask, which does certainly seem to be a neutral gray. So why is clicking the gray mask ok, but a gray card not ok? Either I'm missing a subtle difference, or he's contradicting himself.
joe filer said:
This video is the older version of ACR for Photoshop 7. However,
in CS2 ACR, I find that using the tool on a neutral gray seems to
work just fine.
Click to expand...
Thanks. So I guess you can now click on something that's supposed to be gray, but that doesn't explain the apparent contradiction in the original tutorial.

Thanks for your replies. =)
 
joe filer said:
This video is the older version of ACR for Photoshop 7. However,
in CS2 ACR, I find that using the tool on a neutral gray seems to
work just fine. Even clicking on a black speaker grill cover seems
to work well. I actually had more trial and error sampling the
"white" areas of my calico cat's fur. Anyway, it is only a quick
approximation and may require sampling different areas before you
are satisfied. I would still make final adjustments with PS
adjustments.
Click to expand...
You point out a fact that isn't always obvious in using the 'middle eyedropper' in levels or curves - that you don't have to find a 'gray' spot just an area where the RGB readings 'should be' the same - ie anything from 0,0,0 to 255,255,255. So it works on white and black as well. The problem there being that it doesn't work in blowouts and blocked shadows.
--
Kent

http://www.pbase.com/kentc
For prior discussions on most questions:
http://porg.4t.com/KentC.html
or d/l 'archives' at:
http://www.atncentral.com
 
kirbysdl said:
cspringer said:
He explains that it is a "White Balance Tool and not a Grey Balance
Tool like you would find when using Adobe Levels".
Click to expand...
Yeah, I got that, but he describes using a color tone chart, and
clicking on the colored patches (presumably not the gray/white
patches or else a gray card would have sufficed) to set the white
balance. Specifically, he says "off-white three-quarter tone."
While many other tutorials say to click on an area that should be
white or gray, he specifically says no gray (e.g. a gray card).
Click to expand...
Can you post the other tutorials that say use GREY for "this" White Balance Tool? Again, this is not Curves or Levels but I don't remember seeing any Curves or Levels tuts that said use the White picker on neutral grey...that is what the middle picker is for.

yes...he says many professionals use a "color" tone chart and pick the lighter colors.

I am going to assume that it is sometimes possible to click a grey for similar results because it would actually be the off white you need.
kirbysdl said:
In the end, he ends up clicking on the mask, which does certainly
seem to be a neutral gray. So why is clicking the gray mask ok,
but a gray card not ok? Either I'm missing a subtle difference, or
he's contradicting himself.
Click to expand...
I'm not sure where you are talking about but the picture has a sepia tone. Once he clicked the sepia mask with the White Balance Tool it turns grey. I'm guessing you are looking at the picture after the edit.
 
kirbysdl said:
I thought that when using the white balance eyedropper tool in
Adobe Camera Raw, all you had to do was click a neutral (gray or
white) area and ACR magic would take care of most of the rest.
However, in this tutorial, Russell Brown says that you specifically
cannot measure against a 18% gray card. Why would that be?!
Click to expand...
The common 18% gray card is used for exposure instead of WB. Unless specified, like WhiBal cards, the 18% cards are not 'spectrally neutral' which is what is needed to get the correct WB.

http://wordsandphotos.org/Commentary/HowToGetGreatDigitalColorInAnyLight.htm

--
Kent

http://www.pbase.com/kentc
For prior discussions on most questions:
http://porg.4t.com/KentC.html
or d/l 'archives' at:
http://www.atncentral.com
 
Bruce Fraser in "Camera Raw With Adobe Photoshop CS2" says:

"The white balance tool is best used on a diffuse highlight white that still contains detail, rather than on a specular highlight that's pure white--the second-to-lightest gray patch on the old 24-patch Macbeth Color Checker works well, as do bright (but not blown out) clouds.) (Page 59)

"Use the White Balance Tool for rough white balance, then fine-tune with the sliders[...]...click the white balance tool on an area of detail white. (Page 81)

Maybe this helps to clarify.

Sal
 
I think that the tool's name describes its use: White Balance, not White Point. In my limited experience, the White Balance tool in ACR neutralizes the color casts pretty well, whether clicking on image of a Silver TV, a black stereo speaker, a "white" cat, or a white blouse. A darker value doesn't seem to prevent the tool from working properly.
The tool does NOT change the selected point to pure white.

My question is: What is the ACR tool's sample pixel size? I would still make my final adjustments in PS with an adjustment layer. Certainly using 3 x 3 or 5 x 5 pixel sample

I tried using a dark subject for white balance. Original image as shot (area that I picked to be "black" has rgb value of 8,8,9 when opening the "as shot" in PS. Clicking on that point with ACR white balance tool changed value to 8,8,8 when opened in PS. Doesn't seem too bad to me.
--
My 2¢ worth
My still camera 'evolution' 1950-present:
http://www.pbase.com/filer/image/49099880/original

Joe Filer
Mahomet, IL
http://www.pbase.com/filer
 
kirby,

A gray card is a piece of printed paper, the mask Russell used is PS generated. A gray card, white piece of paper, cloth, a goat nose, the lid of a Pringle's can or any whitish or grayish surface can be used for white balance. However, the question is one of the accuracy of the selected surface as regards to neutrality in digital camera data.

The typical 18% gray card like the Kodak one, is meant for exposure and not for accurate white balance reference. Specular hiltes as well as noise can cause problems when using probling for wb neutrality and that is why a specific tool that is designed with this is mind works better for setting white balance. A case in point the is the Whibal cards, http://www.whibal.com . Accuracy of the tool used will be indicative of your output.

And yes, white balancing and gray or neutral balancing are two distinct issues and shouldn't be confused.
Regards,
VG
kirbysdl said:
Gale Bizet said:
Suggest you watch and listen carefully to him.
Watch a couple times if necessary.
Click to expand...
What a non-answer. I did in fact watch several times but still
didn't understand. Read my restating of the problem below, which
may be more clear than my original statement.
cspringer said:
He explains that it is a "White Balance Tool and not a Grey Balance
Tool like you would find when using Adobe Levels".
Click to expand...
Yeah, I got that, but he describes using a color tone chart, and
clicking on the colored patches (presumably not the gray/white
patches or else a gray card would have sufficed) to set the white
balance. Specifically, he says "off-white three-quarter tone."
While many other tutorials say to click on an area that should be
white or gray, he specifically says no gray (e.g. a gray card).

In the end, he ends up clicking on the mask, which does certainly
seem to be a neutral gray. So why is clicking the gray mask ok,
but a gray card not ok? Either I'm missing a subtle difference, or
he's contradicting himself.
joe filer said:
This video is the older version of ACR for Photoshop 7. However,
in CS2 ACR, I find that using the tool on a neutral gray seems to
work just fine.
Click to expand...
Thanks. So I guess you can now click on something that's
supposed to be gray, but that doesn't explain the apparent
contradiction in the original tutorial.

Thanks for your replies. =)
Click to expand...
 
Thanks for all the replies. After some further research, I think I've got it. Let me try to summarize what I think is true, and then please correct me if I'm still off.

When he says it's not a gray balance tool, he means that it's not meant to adjust the exposure (how much light was hitting the sensor over the course of the shot). Rather, it's a white balance tool and is meant to describe what is considered neutrally white in the picture.

Now when he says you shouldn't use a gray card, I still think that at times it should be acceptable to do so. His intent is to enforce the fact that this is meant for white balance adjustment, but any neutral reference can be used, be it a neutral "gray card," pringles lid foil, or neutral object in the frame. (Incidentally, the neutral side is the shiny side closer to the Pringles chips, right?)

When he says off-white 3/4 tone image, he's referring to something which in real life is a neutral reference, but appears off-white because of the current white balance of the image. 3/4 tone means about three-quarters of the way from the black point to the white point in luminance, i.e. a "bright" yet unclipped region. After clicking this area, the image will be "rebalanced" and the image can be further fine-tuned using the sliders as desired.

Short version: Practically speaking, when using the White Balance Eyedropper tool in ACR, a general rule of thumb is to point it at something bright but not clipped that should be a neutral gray. Clicking that area will reset the white balance to something more appropriate to the clicked area.

I hope I got it this time. Thanks again!
 
kirbysdl
kirbysdl said:
Now when he says you shouldn't use a gray card, I still think that
at times it should be acceptable to do so. His intent is to
enforce the fact that this is meant for white balance adjustment,
but any neutral reference can be used, be it a neutral "gray card,"
pringles lid foil, or neutral object in the frame.
Click to expand...
He specifically says not the 18% gray card and so no, not Any neutral reference can be used. (it would be better than nothing) But he's making that differentiation. The difference between most gray cards and the other things you mention and one that is specific for white balance instead of exposure is that it should be spectrally neutral - ie doesn't take on any of the colors of different light sources. It is well known that some popular 18% cards aren't spectrally neutral, which is what he is pointing out here.

More:

http://www.basiccolor.de/Testimonial/cube/cube_Kundenmeinungen.htm
--
Kent

http://www.pbase.com/kentc
For prior discussions on most questions:
http://porg.4t.com/KentC.html
or d/l 'archives' at:
http://www.atncentral.com
 
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