White Balance - Adjust via RGB histogram

So, I have started using the rgb histogram to determine the white balance of my images. I basically just line up the red, green and blue channels the best I can on the histogram using the temperature and tint sliders. It seems to be working very very well for me.

Does anybody else use this when they are adjusting white balance?

That's an interesting technique, although I've never used it. I've been happy with the "regular" approaches. Are you doing this in DPP?

I think it's an interesting concept, as long as you have some shade of neutral gray in the image to work with (eg. 65/65/65, 137/137/137, 216/216/216).

Without that, however, I have to question whether your technique is actually working. You may be balancing something like 200/200/225 (a blue grey) & getting a cast.

Of course, the big problem is dealing with scenes that have a naturally "unbalanced" mixture of R, G and B but, hey, it's still fun to play around!

I don't understand; you line up the histograms at what point? Along their entire length? Is that even possible? At any point where the histograms truly coincide the resulting image color is grey. That is the definition of neutral grey, R=G=B. If you are photographing nothing but grey cards this method might work admirably, despite being slow and laborious, but most of us shoot multicolored worlds and frequently there is no single neutral grey object in the frame. And even if there is a grey target available, how do you determine exactly the right spot on the histogram? The horizontal axis of a histogram represents tonal levels; for any given value there will be hundreds of thousands of pixels with one or more of their channels at that value, distributed all over the frame, not only on a grey object - if indeed there is one.

The method is slow and laborious because any decent editor will give you the automatic tool to do WB with a single click. Just indicate an area in the photo that should be neutral grey and the software will calculate how much the histograms should be shifted so that at that precise spot , in the image and on a theoretical histogram of only that spot, they will coincide, but not elsewhere.

If your monitor is calibrated and reliable, you would be better advised to forget the histogram and adjust WB until it looks visually pleasing to you.

Heh! Yeah, Elie, go ahead and spoil the fun!

I use this technique sometimes as a starting point for WB.

It happens to be the way TV cameras are white balanced and that's something I know how to do quite well.

I agree though that while it may yield a technically correct WB, it's rarely the right WB.

This technique is hard to explain, but for me and my portraits in my studio it seems to work very very well. I'm sure every image is different with many variables. I just started playing with it last night and it is very quick to do. I should actually just record a little video. Basically, I was getting very natural skin tones by doing that over selecting the appropriate "flash" white balance or "daylight" or setting the temperture of my flash or eye dropper.

It was also much easier than visually looking at the image to determine white balance and yes my monitor is calibrated.

Anyways, just was a thought for some to try.

Hardcore wrote in post #11740132
I basically just line up the red, green and blue channels the best I can on the histogram using the temperature and tint sliders.

In what application are you working?

I agree that for portraits adjusting the sliders is the best method, but I do that while watching the numerical values indicated by the color picker when positioned on the face and with knowledge of what numbers constitute a pleasing skin tone. The histogram has nothing to do with it.

I would have to think that indeed the rgb histogram has much to do with white balance. That is what you are adjusting when you are changing white balance.

Can you share your number for proper face skin tones?

Thanks!

Hardcore wrote in post #11741884
I would have to think that indeed the rgb histogram has much to do with white balance. That is what you are adjusting when you are changing white balance.

Can you share your number for proper face skin tones?

Thanks!

Well, an RGB histogram would show a truly "neutral" scene with the R G and B clumped together (just switch to a Monochrome/Grayscale setting)! But otherwise you will have those curves scattered around, right?

Right.

Well, not in my experience. I started matching the red, green and blue channels to get rid of the color casts on my nd filters. I thought I would apply that to white balance and find for the little bit that I've done, it worked well.

Each red, green and blue channel has a histogram. All I'm doing is basically changing the levels of the histogram to match.

I've added a photo to explain. For this shot, the only light source was natural light coming through the window on a winter day with a few clouds. Camera was set to auto white balance. Presets in adobe lightroom were not even close. Easiest way for me to correct the white balance for nice skin tones was to match the rgb channels to the brightness histogram. Took all of 20 seconds to do and the results where pretty good imo. At the very least it gets you in the ballpark.

Sigh...this doesn't even begin to make sense to me. If you're shooting in a controlled environment (studio), what's stopping you from simply making a reference shot by inserting a ColorChecker card into the scene? You'd get white balance much faster (one click on a neutral patch) that way than futzing around with the Temp and Tint sliders.