white balance/grey card question

Qarik · April 2, 2009

I recently bought light room. One of the white balance oprions when editing a raw file is clciking on a "grey" spot on the photo and BLAMO! white balance is set. So I am assuming the optimum "grey" to be chosen is the from 18% grey card.

Question 1: is that true?

Now as far as I can tell..the white balance from this technique merely adjusts the overall temperature of the photo.

Question 2: is that true? I always thought white balance did more then just change the the temp. For example the green cast from flurorescent light is not correctable through temp alone right? The temp of photo in my head goes from orange to blue and a green color correction is not specificaly in the spectrum? Or is it?

Question 3: I thought the primary function of the 18% grey card is to set your exposure on your meter during the shot. Am I to understand that it's other purpose is color correction as well?

If the answers to these questions are what I think they are then the lesson for me..always shoot raw and always shoot a grey card? heh

pathfinder · April 2, 2009

Actually, an 18% gray card is not the best choice for color balancing unless you know it was designed specifically for that, and even then, a white card is much better. Many 18% gray cards are not color neutral.

As explained by Michael Reichman and others, a 12 bit image can have 4096 discrete tonal values. If there are 5 stops of latitude the sensor can fully capture between highlights, and blacks, 2048 levels are within the first (brightest) fstop. By the third fstop ( or a middle grey) there are only 512. This is substantially less information to white balance off of.

Canon recommends a white card for white balancing in its manuals, and makes no mention of a grey card.

Andrew Rodney has stated here several times to use a MacBeth Gretag Color Checker and balance off the second brightest white. That would be the white box reading 235,234,232. This jpg was one of many I shot evaluating several white balance tool including the Expodisk, A BalanceSMarter true grey reflector, a white source of Titanium Dioxide for a true white, and a WhiBal card among other things.

I prefer to white balance off a white subject that is one step below full white, as in the Gretag Macbeth Color Checker. I am not saying I have never used a gray point, there are even methods to find grey in an image to balance off of, but color balance is usually better when a true white point if used.

The white balance eye dropper is a global edit, and sometimes you have more than one color cast. Say flourescent for highlights, and yellow-orange tungsten for shadows. A global edit will not solve these kinds of issues.

You are correct, the 18% grey card is for reflected light meter readings to set exposure, not white balance.

Qarik · April 2, 2009

hmm..there seems to be a raging debate on this..I am sure it has been discussed ad nasuseum here then and I will do a search

Nikolai · April 2, 2009

I'm not advanced as Jim (and I'm cheap, too:-), so I'm using a very simple black-gray-white card which I got as a freebee when I signed up for NAPP, I think.

I'm trying to take a shot like this before each look and at least once after any major lighting setup change. Then in ACR I select the part of white portion which reads about 200..220, which is the case more often than not, click it with ACR's WB tool, and then apply this setting (and whatever other specific settings I need per look/batch) to other raw images. CS4 does it very quickly, so it really takes longer to type this post than adjust WB on a couple of hundered images.

Just my 0.00002 of the f/stop...

Qarik · April 2, 2009

pathfinder..you are BUSTED!

guess who wrote this post in this thread?
http://www.dgrin.com/showthread.php?t=7434&highlight=white+balance+grey+card

Quote:
Originally Posted by Steve Cavigliano
Trippy,
They were probably talking about using the gray card for setting exposure. Which you can also do with a digital. In a nutshell, a +/- 0 EV reading when metering off the gray card within the scene should get you the best exposure.

Steve

Hi Trippy. Welcome back to dgrin.

That same 18% grey card used for exposure is an excellent source for white balancing in RAW converrsion also - It is actually better than a white card. I also use the Whibal.com set of cards - The studio set is about the size of a deck of cards. Fits in a bag nicely. Just include a sliver of the image of the card along the edge of the frame that will be cropped off in the final image after balancing in PS.

pathfinder · April 2, 2009

Qarik, that is ancient history - over 4 years ago. That is forever is digital time, ya know!! Back before dinosaurs!!

I was incorrect there, but was basing that post in the information I found on the web at that time.

The manual for my 50D, Page 72, says to use a plain, white spot that fills the center metering circle to photograph a suitable image for a custom white balance.

The manual for my 5DMK II, page 66, says "The plain white object should fill the metering circle"

Grey is not mentioned in either manual for a custom white balance in the camera. This may or may not reflect on the eyedropper in LR or ACR of course.

I think the issue is overworked myself. I occasionally will use the eyedropper in LR for white balance on a grey tone or even a black tone with fair success. I just believe white works the best. And is the most reliable.

I have faith the reasoning to use a white, non-specular, subject rather than a grey tone, because there is so much more data in a white tone than a grey tone.

Having said that I found the BalanceSmarter Reflector quite effective, and it is a matte, non specular, grey fold out reflector like an Impact reflector very handy for white balancing and getting exposure at the same time. The grey reflector should yield a neutral jpg with a very narrow spike in the center of your RGB histogram with each channel dead center if it is color neutral, and your exposure, if correct, puts the histogram spike dead center.

Nik - the white, grey, black card you are using came out of one of Kelby's texts I think; that is where I got mine. It is visible to the right of the MacBeth color checker image I posted above. My complaint I have with it, is that it is not a matte surface, but a shiny surface, and it is very easy to get a specular reflection from the white portion with it. When I tested it against my Expodisc, BalanceSmarter reflector, WHiBal cards, and a Spectrasnap color filter ( like the Exposdisc ) I just did not find it as easy to use all the time. Even the gray stripe can yield an occaisional specular reflection ( which is a very bad choice for WB ), and the black is not really black, but just a dark grey.

pathfinder · April 2, 2009

Qarik,

As I look around the web, I also find inconsistent answers also.

Here is a video by Matt Kloskowski, in which he suggest using the WB eye dropper on a medium to light gray rather than a white - http://www.lightroomkillertips.com/2007/white-balance/

It may be that how we set a custom WB in our cameras and in LR or ACR are not done in a similar manner. I have no idea why they would not be, but at least in the Adobe forum for LR killertips, the suggestion is to use a grey neutral tone in preference to white.

That is not true for setting a camera custom WB.

Scott_Quier · April 3, 2009

Qarik wrote:

I recently bought light room. One of the white balance oprions when editing a raw file is clciking on a "grey" spot on the photo and BLAMO! white balance is set. So I am assuming the optimum "grey" to be chosen is the from 18% grey card.

Question 1: is that true?

For reasons already posted by PF, you are better off sampling something white (but not blown) in an image to get a good WB.

Qarik wrote:

Now as far as I can tell..the white balance from this technique merely adjusts the overall temperature of the photo.

Question 2: is that true? I always thought white balance did more then just change the the temp. For example the green cast from flurorescent light is not correctable through temp alone right? The temp of photo in my head goes from orange to blue and a green color correction is not specificaly in the spectrum? Or is it?

You can use a good target and sampling technique to correct for fluorescent color cast (assuming the image was captured with an appropriate shutter speed - but that's a completely seperate discussion

). When you set the WB, you set the temperature and the tint of the image. If it's not exact, it is close enough that the difference is not visible. At least that's been my experience.

Qarik wrote:

Question 3: I thought the primary function of the 18% grey card is to set your exposure on your meter during the shot. Am I to understand that it's other purpose is color correction as well?

If the answers to these questions are what I think they are then the lesson for me..always shoot raw and always shoot a grey card? heh

A good 18% gray card can be used to set the WB - but good ones are hard to find. The card I got from WhiBal is touted as being appropriate to the task, but I've found it to be just a bit warm - causing my shots balanced with it to be just a touch cool. A different target I recently acquired does a bit better.

Travis · April 3, 2009

Anyone have any experience with the PhotoVision target? It is a bit expensive but supposedly is a great target for both exposure and white balance.

pathfinder · April 3, 2009

Travis, it looks like a black, grey, white version of the BalanceSmarter I talked about earlier. I am certain BalanceSmarter has theirs made by Lastolite or somebody.

The need for correct color balance has always been a concern in cinematography and studio work, so these are really not new tools, just rediscovered I'll bet.

The thing I like about these targets is that they are large enough - ~24 inches in diameter - they come in several sizes - small enough when folded up - and do nit require me to turn off my autofocus ( as Expodisc and several others do and then forget to turn AF back on )

Since the BalanceSmarter is a neutral grey and large enough to cover a full frame, I can shoot a quick shot - jpg - in the planned lighting, in Av mode, and immediately get a jpg for a custom color balance for my camera AND, AND ( at the same time ) verify the precise exposure by checking my hisotgram and seeing a single spike in the very center of the histogram. I can then set those Av settings - ISO, Aperture, Shutter Speed - inot my camera in Manual mode , and I am ready to rock.

Takes longer to describe, than to do!!

Or you can just include the target in your image shooting RAW and color correct later in ACR or LR. But for jpg shooters, custom incamera white balance, really is a fantastic tool and time saver.

Travis · April 3, 2009

pathfinder wrote:

Travis, it looks like a black, grey, white version of the BalanceSmarter I talked about earlier. I wonder if BalanaceSmarter didn't have theirs made by Lastolite or somebody.

The need for correct color balance has always been a concern in cinematography and studio work, so these are really not new tools, just rediscovered I'll bet.

The thing I like about these targets is that they are large enough - ~24 inches in diameter - they come in several sizes - small enough when folded up - and do nit require me to turn off my autofocus ( as Expodisc and several others do and then forget to turn AF back on )

Since the BalanceSmarter is a neutral grey and large enough to cover a full frame, I can shoot a quick shot - jpg - in the planned lighting, in Av mode, and immediately get a jpg for a custom color balance for my camera AND, AND ( at the same time ) verify the precise exposure by checking my hisotgram and seeing a single spike in the very center of the histogram. I can then set those Av settings - ISO, Aperture, Shutter Speed - inot my camera in Manual mode , and I am ready to rock.

Takes longer to describe, than to do!!

Or you can just include the target in your image shooting RAW and color correct later in ACR or LR. But for jpg shooters, custom incamera white balance, really is a fantastic tool and time saver.

Thanks Path, I've been using a pocket WhiBal card for awhile and getting decent results. The main problem is that is too small for certain situations so I'm looking to upgrade. PhotoVision is having a 40% off sale right now on their cards so I think I'll be going with the 24" model for $59. It folds up to 10" for easy storage.

pathfinder · April 3, 2009

I have been reflecting on the topics discussed in this thread for a bit, and one thought occurs to me about custom white balancing in camera.

The manufacturer ( at least Canon ) recs a white sheet of paper or subject and does not suggest a gray one. The manufacturer does not know what ISO, or light intensity, the shooter is going to use, or the camera is going to set. (as in some of the zones the camera sets the ISO not the shooter).

Usually when I do a custom white balance I try to use ISO 100, but that means I have enough light to get a good handheld exposure with a white or a grey target. But what if I tried to do this in a dimly lit room at ISO 3200. Using a grey target captures about 1/4 the information that a white target provides as I described above, hence a grey target in very dim light will provide much less accurate information for color balancing.

As I said, I usually try to use the lowest ISO possible if I am going to create a custom white balance. I suspect this would be the approach of most pros. But many prosumer cameras - say a 40D - have modes such as Portrait, or Landscape, or Sports, where the ISO may be set by the camera. In very dim light ( where color balancing can be even more important ) using a grey tone will be more difficult and less accurate than a good, non specular white tone.

At least, that is one reason I can think of that might help explain why Canon suggest white, even though with bright light, grey or white both seem to work pretty well.

Does this seems like a correct argument, Qarik, Scott, others?

rwells · April 3, 2009

Hey Pathfinder,

I know you've done extensive testing with a lot of WB products, and I've commented with you back and forth on a lot of those post. So, what exactly does the BalanceSmarter do better than the ExpoDisk? ** BTW, I do own a Lastolite that looks the same, only smaller. **

I did watch the video on BalanceSmarter's website & it made me laugh. ExpoDisk --> harder to use, doesn't work very well.

I know from your own testing, much less mine, that the ExpoDisk works exceptionally well.

Also, what about all us shooters who aren't in a studio where someone on a stool can hold the "target" to take a WB shot?

As you know, I shoot a lot of sports. That means arenas, fields, etc. Those all have lighting in them that is not present outside of them. I'm just not brazen enough to ask a bull rider holding on for dear life, nor a football player running down the field to hold a "target" for my WB shot.

If you are pre-disposed to have the back * button used as focus, then you don't have to turn your AF off on your lens to take a shot with the ExpoDisk in place. Matter-of-fact, you don't even have to do that. Simply focus on anything, hold the shutter button half-down, then put the ExpoDisk on.

Also, remember that the ExpoDisk has "Expo" in the name. Yes, you can use it for exposure the exact way you described with the BalanceSmarter. You will get a single spike.

An ExpoDisk shot is also a great way to check for dust-bunnies on your sensor, and you don't have to be outside shooting a clear blue sky to do that either.

Still looks to me like the ExpoDisk is more portable/convenient.

I'm not trying to convince anybody here, and I suggest people use what works best for them.

Please, educate me more... I'm always up for learning about new tools for a job.

pathfinder wrote:

Travis, it looks like a black, grey, white version of the BalanceSmarter I talked about earlier. I wonder if BalanaceSmarter didn't have theirs made by Lastolite or somebody.

The need for correct color balance has always been a concern in cinematography and studio work, so these are really not new tools, just rediscovered I'll bet.

The thing I like about these targets is that they are large enough - ~24 inches in diameter - they come in several sizes - small enough when folded up - and do nit require me to turn off my autofocus ( as Expodisc and several others do and then forget to turn AF back on )

Since the BalanceSmarter is a neutral grey and large enough to cover a full frame, I can shoot a quick shot - jpg - in the planned lighting, in Av mode, and immediately get a jpg for a custom color balance for my camera AND, AND ( at the same time ) verify the precise exposure by checking my hisotgram and seeing a single spike in the very center of the histogram. I can then set those Av settings - ISO, Aperture, Shutter Speed - inot my camera in Manual mode , and I am ready to rock.

Takes longer to describe, than to do!!

Or you can just include the target in your image shooting RAW and color correct later in ACR or LR. But for jpg shooters, custom incamera white balance, really is a fantastic tool and time saver.

Nikolai · April 3, 2009

I also would like to throw a monkey wrench into this WB discussion...

While I understand the importance of proper WB while shooting in what may seem as a neutral environment, quite often you may find yourself in a situation when it is NOT neutral and not even supposed to be.
Open fire (bonfire, fireplace, etc.) and sunsets cast a very strong and highly desired warm/golden color. Stage lighting can be totally weird. Trying to "neutralize" it (by whatever mean) will essentially make it as far from "the truth" as it can be.
So, what you guys do in this cases?
My solution is simple: I shoot RAW and then in post I'm trying to make as close (on my calbrated monitor) to what I saw as I can. Some level of subjectivity will naturally take place, but that's kinda inevitable.
The only other solution I can envision is to get an actual color-meter (and those devices are eeeeeeexpeeeeeeen$ive), meter the actual color of some part of the frame (white card, or dress, or whatever), write it down and then try to adjust WB in post to match the readings...

Qarik · April 3, 2009

Nikolai wrote:

I also would like to throw a monkey wrench into this WB discussion...
While I understand the importance of proper WB while shooting in what may seem as a neutral environment, quite often you may find yourself in a situation when it is NOT neutral and not even supposed to be.
Open fire (bonfire, fireplace, etc.) and sunsets cast a very strong and highly desired warm/golden color. Stage lighting can be totally weird. Trying to "neutralize" it (by whatever mean) will essentially make it as far from "the truth" as it can be.
So, what you guys do in this cases?
My solution is simple: I shoot RAW and then in post I'm trying to make as close (on my calbrated monitor) to what I saw as I can. Some level of subjectivity will naturally take place, but that's kinda inevitable.
The only other solution I can envision is to get an actual color-meter (and those devices are eeeeeeexpeeeeeeen$ive), meter the actual color of some part of the frame (white card, or dress, or whatever), write it down and then try to adjust WB in post to match the readings...

I have to go with this. Between grey or white..I think either will get you "close". As a matter of technicality..well let the debates rage. You can fine tune it artistically as you see fit. And as Nik points out..often some kind of color cast is actually preferred. Then it really doesn't make sense to speak of a "true" white balance.

Qarik · April 3, 2009

btw randy..now you have me interested in the expo disc..just started reading up on it. What has me intrigued is that it is an incident light "grey card" not a reflected one.

When thinking about using a traditional grey card I always wondered how it would be impossible to use in some situations like you described or imprecise it might be if the angle wasn't right etc in some other situations. It seems very useful in controlled setups but less and less so in more dynamic ones.

something like the exposdisc wher eyou shoot through it..hmm..interesting.

pathfinder · April 3, 2009

Randy,

I do not want to give folks the impression that I think one method or tool is really better than another for color balancing.

Randy, I had not thought of using an Expodisc to check for dust bunnies. I'll have to give that a try.

Not having to run outside would be great.

Regarding AF, I don't set my AF up with the star button, so maybe that accounts for why I like not having to turn AF off with my BalanceSmarter.

The truth of the matter is that I shoot RAW 98+% of the time and do final color correction in Photohsop like Nik says he does. I balance on a neutral, white or grey and feed free to alter the color balance as I want it.

I agree with Nik, that I frequently find the "technically correct" color balance is exactly NOT the color balance I desire for my image. I frequently end up with images that are much warmer or cooler than the light they were shot in.

For example, this was shot on a dull grey overcast day but I don't think it looks like that. I feel perfectly content to alter the color balance as needed for my image as I did for this one

There are also times when shooting perfectly color balanced out of the camera jpgs are a great advantage - for a sports shooter time is money I know Randy shoots a lot of sports, and some of them like bull riding, are not going to let him into the arena floor to use a reflected grey card.

On the other hand, I can think of stage performances where you might get a chance as the official photographer to shoot a grey card, and would be unable to catch the lights above your head with an Expodisc.

I just think it is always better to know more than just one way to skin a cat

rwells · April 3, 2009

Pathfinder,

Thanks for the reply.

You know that I believe that a person should use the tools that work best for them. I just find that for some reason the ExpoDisk is really misunderstood, usually by those who've never even used one. (I know you have one and completely understand its use/benefits)

Although the video on BalanceSmarter's website is a marketing message, it is, in all my testing and use, completely false about the ExpoDisk, except for the price

I also understand that there are many, many different shooting situations out there and also the photogs goals for the photos look. That's why there isn't just one tool/method. But, that is kind of a side track to discussing WB tools. In that situation, no CBW nor WB tool would likely be the way to go.

I like these discussions because it allows information to be brought forth that otherwise may be hard for some to come by. (Building the knowledge base of dgrin)

Hope you don't think this :duel is what's going on.

pathfinder · April 3, 2009

No problem at all Randy. If I was a sports shooter, like say at a hockey rink, I have no doubt that an Exposdisc or a Spectrasnap would be my tool of choice. The Spectrasnap might be a better choice if you are using a 300 f2.8 or a 400f4 because it is a larger diameter.

In a studio shoot, a BalanceSmarter disc is nice because I can have my subject hold it, and get a reference for white balancing in ACR OR LR2, and set my camera to RAW +jpgs and with a custom white balance, and get jpgs that are spot on on my LCD. and still have a RAW frame to adjust to taste. Best of both worlds to my way of thinking.

Thanks for your kind words on my Route 66 thread in the Journey forum.

jww · April 3, 2009

Scott_Quier wrote:

A different target I recently acquired does a bit better.

..just curious which one you are now using?

Thanks!

ziggy53 · April 4, 2009

Just to completely throw caution to the wind, there is another tool you can use for both exposure setting and "color balance" (not necessarily white balance however), your own palm.

Advantages:

It is almost always with you.

The tones are generally very consistent and, if you are shooting other human subjects, consistency may be more important than absolute values.

It tends to be more reflective than an 18% card (by around 1 stop) which should yield more starting tonal data. (I have used my own palm for setting exposure for many years now with film cameras.)

It is 3 dimensional, similar to other human targets/subjects. This means it also has highlight and shadow tones to sample, something most 2 dimensional targets lack. (Shadow tones are different from simply darker tones in that shadows can reflect different lighting than the highlights. This especially true if you are shooting in an area with a lot of color poisoning like a grassy area, for instance.)

Given the above you should "calibrate" your hand along with a true white card/target of known values, under different lighting circumstances, so that you know how to use the information gathered by using your palm as a color balance target. Once calibrated it becomes a convenient and consistent tool to use as a starting point, especially if you don't have anything else handy at that time.

I'm not saying that your palm is better than other targets, it's not, but it has the convenience and speed factors that other targets may lack at the very moment you may need something, so it's better than nothing and, once calibrated, it's a lot better than nothing.

References ('cause I know you won't believe me):

Setting exposure using palm method:
http://www.kodak.com/cluster/global/en/consumer/products/techInfo/af9/index.shtml
http://markhancock.blogspot.com/2004/08/double-check-exposures.html
http://photo.net/nature-photography-forum/006wuJ

In order to understand how to use your palm for color balance start with the SmugMug article:
http://www.smugmug.com/help/skin-tone

... and then translate that into the values of your own palm taken under controlled conditions and interpolate the values from unknown conditions into the known conditions. (Adjust your recently shot palm tones to proper values for the lighting conditions.)

kdog · April 4, 2009

ziggy53 wrote:

Advantages:

It is almost always with you.

Ok, I have a question. So now you've you set your custom white balance in the camera, taken a bunch of pictures, and brought them into ACR. Which ACR white balance option do you select: As Shot, or Custom?

I think the answer is As Shot. Correct?

Oh one more question. What about the "tint" slider? That seems to preset itself to some magical setting. Does that come from the custom WB as well? Ie, is it set correctly so that I should leave it alone?

Thanks!
-joel

ziggy53 · April 4, 2009

kdog wrote:

Ok, I have a question. So now you've you set your custom white balance in the camera, taken a bunch of pictures, and brought them into ACR. Which ACR white balance option do you select: As Shot, or Custom? I think the answer is As Shot. Correct?

Oh one more question. What about the "tint" slider? That seems to preset itself to some magical setting. Does that come from the custom WB as well? Ie, is it set correctly so that I should leave it alone?

Thanks!
-joel

"As Shot" WB will probably get you close enough, but you should always try to get within reasonable flesh tones using the RAW converter if possible. Convert to 16 bit for best adjustability later on.

If you know the dominant light source you could also specify that as your starting point in the RAW converter.

Use the SmugMug flesh tone tutorial but substitute the tones you have previously calibrated for your palm, instead of those given in the tutorial.

Once you have adjusted the palm tones to match your previously calibrated palm tones that should compensate other tones as well. You may also have to adjust the shadow tones as a separate eye-dropper sample.

Remember, this is a "color balance" operation, not a "white balance" operation so the methodology is different. The results should be similar.

You would do these same things if you needed to balance another known color, brass for instance. If you wanted the tones of a brass item in an image to be accurate you could work from a known sample. The human palm is just a "handy" reference. (Get it, "palm", "handy", oh my wit is wasted ...)

kdog · April 5, 2009

ziggy53 wrote:

The human palm is just a "handy" reference. (Get it, "palm", "handy", oh my wit is wasted ...)

Is that your rule of thumb? Either way, I think you nailed it.

No flesh tones in this shoot. They were 28 different samples of exotic gemstone tiles that were being shipped to a customer. I took pictures to archive them so that they can be duplicated in the future. So there's going to be a bit of guess work to get the colors just right.

Thanks for your insight, Ziggy.
-joel

white balance/grey card question

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