That's a difficult question.
Human vision is based on our optical pathway, but also our cognitive processing of those signals, both of which are incredibly difficult to reproduce with a camera.
For example, when I was in elementary school, our classrooms were lit with the (then) standard fluorescent bulbs, which put out a greenish light. But nobody noticed that it was greenish... it looked like it was just normal, white light. Obviously this was because our brains were compensating for the color shift to match our expectations for known colors. But when my 4th grade teacher took photos of us under the classroom lights, everything looked greenish.
Were the photos accurate? They accurately represented that a greenish wavelength was present, but they did NOT accurately depict what we saw. They needed to be white balanced for that.
But what we see is ultimately subjective, and also dependent on our experience and environment. There's a huge amount of anthropological literature about color perception, for example. People who live in cultures who don't have words for certain colors, for example, have much more difficulty distinguishing between those colors and similar colors. When we enter a new lighting situation, and our minds have not established color base-points, we have trouble distinguishing colors. In low light, the cones (which see color) on our retinas do not work very well, and consequently, we rely heavily on our rods (which don't see color), so much of the color that we believe that we see is actually being filled in by our minds and past experience, and it is frequently inaccurate.
There are many devices available for standardizing color. The
x-rite Passport is a popular one. The passport basically has a bunch of standardized color swatches that you take a photo of when you start taking photos in a particular lighting situation, and then can use to check the white balance against when you're post processing. And it works, as far as it goes... when you process the photos, the white in your photo will match the white on the actual passport surface.
But consider this situation:
Suppose you're out for a walk on a hazy, warm summer evening, and the sun is getting low in the sky, and the light on your landscape picks up that beautiful golden hue that makes summer evenings so gorgeous. If you were to set your Passport out in a field in that light, bathed in the golden glow, the white patch on it would not appear white to you... it would appear warm and yellow/orange.
Now, suppose you get back home and process that photo such that the white on the passport appears to be pure white. Again, it will be accurately representing the color of that white patch under standardized lighting conditions, but it will also have stripped the entire image of that nice, golden warmth. [*sigh* Can you tell that I live in Seattle and can't WAIT for some sunlight?]
Ultimately, the only way to get that photo to match your perception of it is to remember what it looked like, then go home and make the adjustments in any way that you know how to make the photo look like what you remember.
And the same is true of reef tank photos... your guide will always have to be your own memory and experience.
Hope that makes at least a little bit of sense!
- Matthew Gore
