Neutral Colors

[KevinStecyk]

I am wanting to understand better neutral colors. From my reading, I get the impression that I want to my balance my colors using a neutral color, which is red, green, and blue having the same value. In Photoshop, if you use an eyedropper, it shows you the red, green, blue values in RGB mode.

If a color is not neutral, does it then suffer from a color cast? In other words, what is special about a a neutral color? And why do we use it for color balancing purposes?

Further along this thought, if you were outside shooting during the golden hours (early morning, late night) and you wanted to capture the color cast, would you dial in an arbitrary number for your color temperature? If so, what value? I know that if you use AWB, you'll get an arbitrary and unpredictable value. Moreover, if you take several shots, the shots will vary in color temperature from picture to picture because the camera will guess the appropriate value for AWB each time.

So my questions come back to, what is neutral color and why is it important?

[Jerry Skrocki]

Neutral grey theoretically contains equal amounts of red, green and blue.
By placing a grey card in your photograph you assure that color balance between the three colors is equal and that the colors represented in your photo are true. The 18% grey card method is a carryover from film photography.

Some digital cameras allow for custom white balance and a grey card allows for an accurate setting. If your digital camera does not have have a custom setting, photographing a grey card in the same ambient light will allow for Photoshop or ACR correction with the grey eyedropper tool.

I always photograph outdoors with white balance set to daylight setting. I also always shoot RAW which makes the setting irrelevant.

[KevinStecyk]

Originally Posted by Jerry Skrocki

Neutral grey theoretically contains equal amounts of red, green and blue.
By placing a grey card in your photograph you assure that color balance between the three colors is equal and that the colors represented in your photo are true. The 18% grey card method is a carryover from film photography.

Some digital cameras allow for custom white balance and a grey card allows for an accurate setting. If your digital camera does not have have a custom setting, photographing a grey card in the same ambient light will allow for Photoshop or ACR correction with the grey eyedropper tool.

I always photograph outdoors with white balance set to daylight setting. I also always shoot RAW which makes the setting irrelevant.

Jerry, I thought neutral gray was 128,128,128. But I could have anywhere from 0,0,0 (black) to 255,255,255 (white). I think what I've got is simply a black to white gradient? Anything with color is then no longer all the same values? So concrete and steel are often good neutral colors for white balance corrections because they are along the black / white continuum?

I am using a Canon 20D and 40D, so I can set the white balance when shooting. Which is great if I want the shot without the color cast. But during the golden hours, I might WANT the color cast, in which case using a target defeats the very purpose? For example, if I wanted a brilliant warm color of the morning sun while photographing the Golden Gate Bridge, then using a target (or similar device) would give me the wrong result. It would eliminate the warm color cast.

Yes, I have heard that when shooting raw, which I do, then it doesn't matter about the color balance because you can correct for it afterwards, assuming you have a target or something to use for calibration. However, I prefer to get it as close as possible in camera.

I am not sure of my next few statements, so I am testing. Although early morning and late evening sun provide a warm feeling to the photograph, the color red itself is actually a low temperature (blue being a high color temperature). Thus, I would estimate a low color temperature in the camera white balance setting. To get an accurate color temperature reading, I probably need a specialized color light meter. So the best I can do is estimate or adjust with a raw converter to my liking.

Any thoughts?

[Jerry Skrocki]

Kevin,

You are right about the numbers, as long as all three are equal you will get a balanced reading. White paper can also be used by a digital camera for white balance.

Accurate white balance should not be a detriment to your sunrise/sunset photos. I would think exposure is more critical and a graduated neutral density filter would be ideal. Shooting RAW gives you more latitude in the area of white balance but not exposure.

Here is a good article by Jeff Schewe explaining white balance and RAW:

http://www.napavalley.edu/Projects/1...balanceRAW.pdf

[KevinStecyk]

Originally Posted by Jerry Skrocki

Accurate white balance should not be a detriment to your sunrise/sunset photos.

Hi Jerry,

Thank you for replying with additional information.

I know how to achieve an accurate white balance, but sometimes--for example, sunrises and sunsets--an accurate white balance is not desired. That is, you want something that is actually and truly pristine white to appear golden red from the early morning or late evening sun. So an accurate white balance, in this instance, is what you trying to avoid.

So the question becomes, how do we set the camera to record what our eyes see? If we simply use AWB, who knows what we'll get during sunrises and sunsets. If we use a target, we eliminate the very effect we're trying to capture. My belief--because I am not certain--is that one needs a meter that captures color.

Here's one from our sponsor B&H: Kenko | KCM-3100 Professional Color Temperature Meter | KCM-3100

Armed with this $1400 baby, you could perhaps determine the color temperature, set your camera to the same color temperature, and then you should capture on pixels what you eyes see?

[KevinStecyk]

Originally Posted by KevinStecyk

Armed with this $1400 baby, you could perhaps determine the color temperature, set your camera to the same color temperature, and then you should capture on pixels what you eyes see?

Actually, that might be equivalent to setting the proper white point using a target. So perhaps, just dial in a comfortable normal daylight temperature, and then it will appear red. In other words, it will be subjective anyway?