Custom White Balance Revisited [Not a RAW Discussion]

[DwightMcCann]

Some time ago I started a thread about Custom White Balance (http://photography-on-the.net/forum/showpost.php?p=1383516&postcount=1) because I was so blown away with how powerful it was. Unfortunately it got diluted by discussions about RAW for reasons I cannot fathom as there are enough discussions about RAW to sink a battleship. Not only that but I whole heartedly agree that RAW is better [even though I almost never shoot RAW.] But I am back, suited up once again in Teflon® because I know the RAW shooters will want to steal this thread explaining that it is just that everyone should shoot RAW and handle white balance in Post Processing and they are obliged to flog us about this at every opportunity, too bad if it has nothing to do with the topic ... of course, this is simply not true.

Today's presentation is a demonstration that correcting white balance in post processing is not trivial, at least in jpegs (but I believe that is irrelevent.) In the embedded image, the upper left photo was shot with tungsten white balance. The lower left image was shot with CWB using a white piece of paper. Both of these images were presented in the original thread. The upper right image is color corrected by using the white shirt of the right most guitar player, Jack Sizemore (of BrittonJack, see original thread), as a white point. You will notice that the upper right and lower left images are not nearly equivalent!

So, I expect we will hear lots from the RAW shooters (since I baited them in here in my title) but I am hoping we will hear from someone(s) who can shed some light on this issue.

[johnstoy]

I noticed, that you had your white balance Custom set, as indicated in your recent photos EXIF...I know the instructions are in the manual for the setting of custom white balence...

I'd be interested to see the more experienced photographers comments on this subject...as I'm a relatively new owner of a 30D...

According to your samples, customizing is a very powerful tool for WB balance adjustment...

[In2Photos]

here is my best educated guess:

The white sheet of paper has a different color value than the shirt used in PP. Use the eyedropper tool in ACR and see what values are given for the shirt in both images. Also, try going to the lower left shot and click on his shirt for custom WB. Do you get the same results? Thw white in the original corrected image still doesn't look white.

[DwightMcCann]

Mike, the white may not be exactly white (depending on where I touched it) but nowhere on that shirt is white going to make those jeans blue! I think CWB is more than just color temperature and I'm hoping someone knows! BTW, love your title!

[RAitch]

CWB is also tint.
Also, the white points on those images don't seem exact. The red and green values are slightly off.

Mind you, setting a white point won't totally correct colour... a lot of that comes from the midtone calibration.

When you set a CWB from an image (assuming you have 0EC locked in) you'll actually be exposing the white piece of paper as neutral grey... so in a sense, you're controlling the mid point colours.
I wouldn't expect to be able to set colour balance from white only... or black only for that matter.

And back to RAW... I shoot RAW and also custom WB when it's needed. After all, your CWB will show in the RAW converter under the "As Shot" preset... so you have a very good starting point for tweaking.

[E-K]

Today's presentation is a demonstration that correcting white balance in post processing is not trivial, at least in jpegs (but I believe that is irrelevent.)

Whether it's JPEG or raw is not irrelevant. For raw it is trivial to correct in post processing assuming you have a suitable gray reference point (there I bit ;) )

In the embedded image, the upper left photo was shot with tungsten white balance. The lower left image was shot with CWB using a white piece of paper. Both of these images were presented in the original thread. The upper right image is color corrected by using the white shirt of the right most guitar player, Jack Sizemore (of BrittonJack, see original thread), as a white point. You will notice that the upper right and lower left images are not nearly equivalent!

So, I expect we will hear lots from the RAW shooters (since I baited them in here in my title) but I am hoping we will hear from someone(s) who can shed some light on this issue.

Passing the eye-dropper around the top images shows that the red channel looks like it is saturated. In other words it's probably not going to be possible to correct the white balance as the information just isn't there.

If you're shooting JPEG then it's best to get the WB correct in the camera. First choice is custom, second choice is presets/temperature and last choice is AWB.

e-k

[DwightMcCann]

Excellent feedback, especially the point about the red channel saturation making it impossible to correct the white balance ... I am guessing that channels saturate in RAW also so even shooting RAW might not correct the White Balance that CWB does, even with a gray card in the scene.

[SkipD]

I think part of the problem with the upper right image in the first post was that the white shirt was, in fact, overexposed. Had there been a standard gray card (truly neutral color and mid-tone gray, that is) in the middle of the group to use the eyedropper tool on, I would suspect that you would have had much better results - equivalent to the CWB shot.

If the "white" (or neutral) reference is not properly exposed in the shot that you are using for the neutral reference, there's no way to get a proper white balance calculated from it because one or more of the color channels is likely to be blown out.

[Bodog]

If the "white" (or neutral) reference is not properly exposed in the shot that you are using for the neutral reference, there's no way to get a proper white balance calculated from it because one or more of the color channels is likely to be blown out.

A very good reason to use a grey card rather than white for CWB.

[RAitch]

Well hold on here.
How are you correcting the WB in PS? With a curves adjustment using the eyedropper?
When you set the black and white points, you're basically setting the contrast clipping of the curves. Mind you, if you choose a section that's not white or black (with colour cast) it will affect the colour in your image... but only a bit.

When you play with the mid tone dropper, you'll see some massive changes.

While the red channel may be saturated, that area is still pretty close to white. Being a little bit off of perfect balance (like 250-250-250) won't affect the overall colour balance too much.

The key is the grey card... which controls the mid tones. When you use the midtone eye dropper in curves, you'll see the colour just snap right in when you click on the card. Switch the curves dialog to an individual channel and see what the adjustment is doing to each channel.

When you shoot a grey card (like somebody holding one in scene) chances are that it'll be exposed around mid grey.
The best way would be to shoot a grey card and fill your spot meter with it with 0 exposure compensation dialed in... or manual settings so it'll fall in the middle of the meter. Then you know the card will be exposed in the mids.
Then, just select that image for your CWB and away you go. You won't have to adjust WB in PP afterwards (unless the lighting changes on you while you're shooting -- just repeat)

You can also use a white sheet to do this. The fact is, if you fill your viewfinder with the paper, and your EC is 0... it'll expose both a white sheet, grey sheet, or even black sheet the same. Obviously, the grey or white will reflect colour and light better... so don't use black!! ;)
SO, don't think that a white sheet won't work because it'll be close to blowing out. It'll get metered down to 18-grey.

Channels will also saturate in RAW, but the range is higher. JPEGs are limited to 8 bits per channel (256 levels in each colour) where RAW captures in 12 bits per channel... and stores in a computer-friendly 16-bit (double 8 ) format (due to memory indexing design). 12 bits will give you more levels of data (like 4000 or so theoretically).
You'll still get blowouts... but this is why you're able to create multiple exposures from the same RAW file (for example).

[RAitch]

Dwight, to get a WB correction to match CWB out of the camera, you will need a good mid-grey reference to get it perfect.
Matching from a white point won't work as you plan. certain channels can blow out (hurting your colour ratios) but there are also other reasons.

Notice how most digital noise is in the dark zones of your image? If you think about your image holding 5 stops of light, the brightest stop contains as much data as the sum of the other 4. This means the darkest stop has a fraction of the number of levels to represent that light... this means small changes in data can produce major image changes.

On the flip side of that, the brightest stop has ALL KINDS of data... so minor variations in colour cast won't be as obvious in the high registers... than, say, in the mid tones.

Ideally, you want to shoot in camera with CWB set off of a white sheet or grey card. If you don't do that, you should have a reference card with white, black and mid grey. If you set ALL 3 points, you'll get a good result... and will define a nice contrast range for your image at the same time.

[RAitch]

A very good reason to use a grey card rather than white for CWB.
As mentiond, when you're shooting a white or grey card... and it fills your spot/partial meter... and your EC is set to 0... they'll both be exposed the exact same... just the white sheet will use a faster shutter speed.

If it's a reference point in an image (like a paint chip size) that you're going to use the eyedroppers on... than you're right... white can easily blow out.
But you'd still want to use a white-grey-black card... ideally.

[odvdveer]

I could get the jeans to turn blue when using the center eyedropper on the mortar of the chimney.

Olga

[E-K]

Excellent feedback, especially the point about the red channel saturation making it impossible to correct the white balance ... I am guessing that channels saturate in RAW also so even shooting RAW might not correct the White Balance that CWB does, even with a gray card in the scene.

Not with the same exposure since the CWB comes into play after the raw image is captured.

e-k

[E-K]

While the red channel may be saturated, that area is still pretty close to white. Being a little bit off of perfect balance (like 250-250-250) won't affect the overall colour balance too much.

The whole image appears to have the red channel saturated (the brick wall, the white shirt, the skin tones, ...) To me this strongly suggests that there likely was some clipping of that channel as well. If there was clipping then no amount of colour correction can recover the image as that information has been lost.

e-k

[RAitch]

The whole image appears to have the red channel saturated (the brick wall, the white shirt, the skin tones, ...) To me this strongly suggests that there likely was some clipping of that channel as well. If there was clipping then no amount of colour correction can recover the image as that information has been lost.

e-k
If you read the rest of what I typed, you'll see that I agree that there's clipping, but also that making adjustments at the white point won't drastically correct the colour. And that the white portions of the image contain much more data... so minor changes in colour will be that, minor. Minor changes in colour in the midtones are detected much more easily.

It's just like if you're trying to correct colour manually using curves.. just how much can you change the image if you're only adjusting a point in the curve at the corner? If you want overall image colour/tone changes, you adjust from somewhere in the middle (and tweak the ends after).

Only changing based on either the white or black point will tend to adjust the angle of the curve line... in effect changing the contrast of the image. If you adjust based on the middle, the curve must bend and has more ability to affect the entire image.

The whole point is you shouldn't set white balance/colour corrections ONLY on a white point. Colour correction will always be more accurate off a mid point (and even better from all 3 points).

[E-K]

If you read the rest of what I typed, you'll see that I agree that there's clipping, but also that making adjustments at the white point won't drastically correct the colour. And that the white portions of the image contain much more data... so minor changes in colour will be that, minor. Minor changes in colour in the midtones are detected much more easily.
....

The whole point is you shouldn't set white balance/colour corrections ONLY on a white point. Colour correction will always be more accurate off a mid point (and even better from all 3 points).

I did read the rest and I agree with you in general. I just wanted to make it clear that I wasn't only talking about the white point. I meant that the red channel was out of wack for the whole image.

So even if they had a mid-tone gray in the image to work off, you could never get the image to look like the bottom left. This is with respect to JPEG which is the constraint the OP had made in their post. If it had have been a raw image then I agree this could have been done.

So to summarise, I agree with you completely that balance/colour corrections only on a white point are insufficient. My point was just that when the colour is way off, like in this image, having a mid-tone reference in the image may help but would still be insufficient. So if you are shooting JPEG try to get the WB correct in the camera rather than trying to correct it in post-processing.

e-k

[RAitch]

Exactly.
Mind you, setting off of all three points will help to eliminate some of the clipping effect (by balancing the colour) but you WILL still have issues re-generating data that's lost from clipping as you say.

It's always best to get images out of the camera in the best shape as possible so minor adjustments can be made. The more PP adjusting you have to do, the more the image will suffer.

[DwightMcCann]

I really appreciate you guys pounding away on this. First, you were right that I did the wrong thing to correct white balance ... all I did was adjust the contrast, sigh. But then I went back to the image and tried to do it right with the midtone dropper and then adjusting the saturation because the contrast was so high ... and it is not possible as there just isn't enough information in the jpeg so when I get it close in one color another is distorted or lost or clipped. I'm not facile with editing so maybe it's just my technical skill. But this is just another example of why CWB is so potent and the value of RAW in difficult situations. Thank you.

[RAitch]

Most of the time I just use the individual channels in a curve layer and make some manual adjutments starting with bending at a center point. Go one way, find where it's too much... go the other way and find where it's too much... then narrow down to the sweet spot.

Once you have the general tones tweaked, you can go and bend the lines at the brights and darks to fine tune the low and high key colour tones.

Generally, I go through each channel twice... because as you said, once you change one colour, it can affect another. Normally, when you find the best curve for each colour, you won't have to move it much later.

This is my general analog PS editing technique... and it's just subjective to what I think the image looks like and if it's what I want. I can't pick out a perfect neutral grey from an image by myself! ;)

The less editing you have to do, the healthier your image will be. CWB is very important. And using RAW is not an excuse to not use CWB. Having the "right" values saved in the "as shot" settings are very handy... so you don't have to interpret the right values yourself later on during conversion... and that's saved in the RAW file.

There are so many other reasons to shoot RAW... having a wider range of tones to work from has to be the most important... JPEGs in digital capture clip way to easy.

Maybe some day we'll have cameras that capture data in true 32-bit per channel colour and software that can manage that. Then we we'll be able to represent the human eye... and won't have to decide between blown out sunset... or foreground silhouette... or bracketting for HDR.

[DwightMcCann]

Rich, thanks again.

[In2Photos]

Mike, the white may not be exactly white (depending on where I touched it) but nowhere on that shirt is white going to make those jeans blue! I think CWB is more than just color temperature and I'm hoping someone knows! BTW, love your title!
I noticed this same thing last night Dwight. My daughter was wearing a white shirt in a shot and when I used that in ACR I got a very blue photo. I ended up just using the slider until I thought it looked best. I also noticed that when adjusting WB it also affects clipping. At one temp I had channels clipped, at another temp they were not. I think everyone else has given you the answers you (and I) need, though.

PS I like my title too.:)

[RAitch]

Well, if you have an image that's near saturation in the red channel already... and then you warm that up with temperature and tint, it's going to saturate the reds even more and push those values over the line.

If you have the option, it helps to look at an RGB histogram in camera instead of the normal one. You may see that your blue channel is way to the left... and if so, you can prepare you mind for applying some noise reduction later on... or think to drop the ISO if you can manage it.

It's pretty cool to see just how different each channel can be... especially when you're taking landscape shots.

Fortunately, to avoid clipping, you can adjust contrast. Many people don't think of doing this, but when you're taking JPEGs in harsh lighting, you can go into your profiles and drop the contrast WAY down. That will condense the histogram towards the center and make your image look flat.
In RAW conversion, you can also move that slider to the left.

The advantage is packing more light range into the same photo and avoid clipping. Later on, in PP, it's very easy to add contrast with some masked softlight layers... or inverted USM layers.

The opposite is also true. If you're out taking pictures in a snow storm, your histogram can tend to be very narrow in the middle. If you crank up your contrast settings (or convert using higher contrast) you'll spread that histogram out and retain a higher variety in tones.
Having that out of the camera again will make your PP edits smoother.

[DwightMcCann]

I noticed this same thing last night Dwight. My daughter was wearing a white shirt in a shot and when I used that in ACR I got a very blue photo. I ended up just using the slider until I thought it looked best. I also noticed that when adjusting WB it also affects clipping. At one temp I had channels clipped, at another temp they were not. I think everyone else has given you the answers you (and I) need, though.

PS I like my title too.:)

Yes, I am more convinced than ever that CWB is an essential tool without respect to RAW/JPEG. Fortunately, when shooting shows at the casino there is generally such a huge variety of light and such good sunlight spotlights that it is not an issue.

[DwightMcCann]

Well, if you have an image that's near saturation in the red channel already... and then you warm that up with temperature and tint, it's going to saturate the reds even more and push those values over the line.

If you have the option, it helps to look at an RGB histogram in camera instead of the normal one. You may see that your blue channel is way to the left... and if so, you can prepare you mind for applying some noise reduction later on... or think to drop the ISO if you can manage it.

It's pretty cool to see just how different each channel can be... especially when you're taking landscape shots.

Fortunately, to avoid clipping, you can adjust contrast. Many people don't think of doing this, but when you're taking JPEGs in harsh lighting, you can go into your profiles and drop the contrast WAY down. That will condense the histogram towards the center and make your image look flat.
In RAW conversion, you can also move that slider to the left.

The advantage is packing more light range into the same photo and avoid clipping. Later on, in PP, it's very easy to add contrast with some masked softlight layers... or inverted USM layers.

The opposite is also true. If you're out taking pictures in a snow storm, your histogram can tend to be very narrow in the middle. If you crank up your contrast settings (or convert using higher contrast) you'll spread that histogram out and retain a higher variety in tones.
Having that out of the camera again will make your PP edits smoother.

Excellent observation and point about lowering contrast in camera to reduce clipping and pointing out how reviewing the histogram to decide what to do is more clever me. Luckily, again, these are not problems at the casino, generally, although I am now going to review my images and settings ... in both cameras, sigh. Thank you, again.

[RAitch]

Well, for the most part, you can take some sample pics early on at the show to give you an idea of where you're at. I know the lighting (colour and amount) will be changing throughout a show, but if you're already in the ballpark, you should be pretty good.

Sometimes you might want high contrast shots in there to purposely blowout lighting or catch some beams.... it depends as you'd know.

From what I've seen in your work, you have a knack for live performances. I don't think you have anything to worry about.

Depending on the equipment, you can set-up profiles for different situations. Perhaps copying the normal mode into a user spot and increasing the contrast on one... and decreasing on another. My 30D is set-up to bring up the profiles when I press the SET button... so changing it is very fast. Other bodies won't exactly work like that.

Just curious Dwight... why don't you shoot RAW? Seeing what you can do with a JPEG already... I bet you'd be really impressed with what a RAW can do to help you out.

ESPECIALLY when it comes to double-exposure. I use that trick quite a bit to get rid of hot spots. Open another RAW version of the same image, just drop the exposure/brightness down a bit until the hotspots look better (like flash on faces/skin) and then drag that layer into your other photograph. Add a black mask to the layer and start painting with white to tone down the highlights selectively.

Are you concerned with the extra file size... or the extra time for the conversion? To be honest, I think the WF for RAW would make an event photographer's life much easier. You can apply the same exposure/WB/colour/contrast to a batch of similar images very quickly.

[DwightMcCann]

Well, for the most part, you can take some sample pics early on at the show to give you an idea of where you're at. I know the lighting (colour and amount) will be changing throughout a show, but if you're already in the ballpark, you should be pretty good.

Sometimes you might want high contrast shots in there to purposely blowout lighting or catch some beams.... it depends as you'd know.

From what I've seen in your work, you have a knack for live performances. I don't think you have anything to worry about.

Depending on the equipment, you can set-up profiles for different situations. Perhaps copying the normal mode into a user spot and increasing the contrast on one... and decreasing on another. My 30D is set-up to bring up the profiles when I press the SET button... so changing it is very fast. Other bodies won't exactly work like that.

Just curious Dwight... why don't you shoot RAW? Seeing what you can do with a JPEG already... I bet you'd be really impressed with what a RAW can do to help you out.

ESPECIALLY when it comes to double-exposure. I use that trick quite a bit to get rid of hot spots. Open another RAW version of the same image, just drop the exposure/brightness down a bit until the hotspots look better (like flash on faces/skin) and then drag that layer into your other photograph. Add a black mask to the layer and start painting with white to tone down the highlights selectively.

Are you concerned with the extra file size... or the extra time for the conversion? To be honest, I think the WF for RAW would make an event photographer's life much easier. You can apply the same exposure/WB/colour/contrast to a batch of similar images very quickly.

Thanks again ... I have 1D MII[N]. I need to look at profiles.

Why don't I shoot RAW? Why don't I use Photoshop? These are really the same question. The truth is: I have worked so hard to get a system that works [jpeg and PhotoImpact] and is successful for me that I am just burned out. And even as a computer programmer I have run into so many problems at every single step of this process that I have become risk averse. One tiny example ... I bought RSP and it took me about six months to get to it. Within a month of trying it they were bought up and all the time I invested was useless. Also, I am involved in websites and have the same problems there with Adobe buying up Macromedia. I would love to convert to RAW and Photoshop (I have PS CS2 ... actually the whole studio thing ... legitimately) but the time investment is huge. I keep looking for classes or seminars in my area and they either conflict with my schedule or are too far away.

I currently shoot with 8GB cards in both cameras. I could easily buy another pair of 8GB cards. Equipment is not an issue. It is learning a whole new set of applications when I have a set in hand with which I think I am quite skillful and am certainly successful. But I agree that I need to make the effort at some point as there are just too many benefits to continue to ignore [some might say I am in denial.] Maybe right after I finish working my way through Project 7's 42nd Street CSS tutorial and getting my backup computer working (oh, that's been another timesink because of horrible vendors) and finally get the rest of the Bios and portraits and PR images and Covers page for the band I am working with ... oh, and I have a fulltime day job, too ... then I'll get to PS and RAW ... honest! :rolleyes:

[JoseC]

I want to thank you to made me try the custom white balance on my 350D.
I had bad experience with my G3 but on the 350D the custom WB
works very well.
I usually shot in raw, and use rawshooter so I can correct the WB, but using the custom WB is a very good tool because it is not so easy to correct the right WB during post processing.
Best Regards
Jose

[DwightMcCann]

I want to thank you to made me try the custom white balance on my 350D.
I had bad experience with my G3 but on the 350D the custom WB
works very well.
I usually shot in raw, and use rawshooter so I can correct the WB, but using the custom WB is a very good tool because it is not so easy to correct the right WB during post processing.
Best Regards
Jose Tres Bien. C'est ne faire rien. [45 year old high school French.;)]

[RAitch]

I hear ya bud... time is gold... and like I said before, you're doing well with what you're doing and how you're doing it.

What's with the 7's 42nd Street CSS tutorial? Sounds meaty. I have some CSS tutorial videos... but fell asleep watching them drone on about some personal experiences or something.

I found the Lynda.com "Enhancing" videos to be great for a PS lesson... to be honest, I don't think you'd get anything better in a classroom... honestly.
The whole thing is geared for photographers from a photographer... not a techie guy that just knows the ins-and-outs of PS... he shows you how to actually accomplish stuff in PS for your images... and I use his "workflow" and "approach" for my edits.

PS opens some pretty huge doors. I've been using it since version 4 on and off... so it's second nature for me.


You can always use a RAW converter to convert to TIFFs and then continue as you normally do... BUT, that will just add another step to your workflow.
Once you see what RAW can do, there really is no turning back... so be careful!!