white balance questions

[jli]

White balance correction is a process for adjusting color casts in images recorded by the camera sensor. The human visual system performs an analogous process so that objects that we think should be white really seem white, instead of blue/orange-tinged white. Setting white balance is just applying this to the digital image data.

Now... why is setting white balance necessary? If the sensor records incoming light "faithfully", can't we use our built-in natural WB correction when we view the image again? Does this fail because we'll often view the faithful image in different light, throwing off our WB "calibration"?

Or maybe the problem is the faithful recording part? My camera doesn't have a "faithful" option for WB, but 6 or 7 choices for different settings at different color temperatures. Would the daylight setting be "faithful"? Would faithful be some sort of even, balanced white?

Please fix my ignorance!

[PowerPix]

You're confusing yourself. STOP!!!

You might find something useful here: Understanding White Balance

[wulf]

Faithful recording? You'll want RAW shooting mode for that. Otherwise your camera will make various calculations to shrink the data to JPEG format (widely viewable and much smaller file size).

That said, I use JPEG mode most of the time and pick an appropriate WB setting (or set it using a white or grey object). Definitely have a read of the article PowerPix mentioned.

Wulf

[zona5101]

I think the OP is asking since our eyes have "built in wb" when we view the original scene, why don't our eyes make the same "auto-adjustment" when we look at the picture of the original scene.

i mean it works for cyborgs, right?

[chl0e]

My Dad told me that if we saw a picture with an "incorrect" white balance that filled our entire vision, we'd see it as the right colours.

So I guess the reason is that the brain can only sort out the colours if it's the entire field of vision and not in comparision to other stuff...

Sorry if that's not what you were asking xD

[Chip]

Originally Posted by jli

The human visual system performs an analogous process so that objects that we think should be white really seem white, instead of blue/orange-tinged white.

If I understand what you're asking: Humans are in fact good at telling what is white under different lighting conditions. But, whites do not always appear the same to the human eye. For example, a white wedding dress placed under an incandescent light will look different when placed under a florescent light. Similarly, a white bird on cloudy day will look different than the same bird on a sunny day.

If I pay attention to these changes in the light source, I get better at "seeing" the color of the light I'm shooting in, and can better adjust the white balance in camera, so that the white captured by the camera matches how I want the white to appear in the photo.

Hope this makes sense and comes close to answering your question.

[sk66]

In everyday life, the things you view are not just viewed but more directly experienced...You are walking on grass and grass is "green". That's snow and snow is "white".... Because you "know" what everything is your mind can automatically color correct. You actually do "see" the color cast, you just tend to ignore it because it is not relevant to the experience. (and learning NOT to ignore these things is part of learning to "see like a photographer")

However a viewed image is not experienced "directly"...it is taken "out of context"....I do not know that is snow I am looking at until it becomes obvious (already correct colors) or I determine it to be snow.. (i.e. try to determine the difference between snow drifts and sand drifts without color context). And color cast is relevant to the experience with a viewed image, it is not ignored, because viewing and interpreting IS the experience.