Weird Color Problem

[Josh66]

I guess that's possible. I hadn't considered that.

 

[Garbz]

The WhiBal is supposed to be neutral across the entire spectrum (they say it is, but obviously - I have no way of independently verifying that) - would that not solve the problem you're talking about?

No different problem. A grey card is a grey card. You light it up with anything such as a green and blue light and then white balance off it, it'll show up as a neutral grey.

However in this case of the green and blue light, if you then put a colour checker card under it you'll notice nice greens and blues and really really crap reds (assuming you can actually get the colours neutral enough to make the effect).

Think of outside, tungsten, and halogen lights as a smooth curve, because that's what it is (black body spectrum with a specific colour temperature). Hold a CD up to that light and you'll create every colour of the rainbow. But compare that to a fluorescent source and you end up with sharp peaks carefully placed by selecting phosphorus that give off light that makes the result look white. Everything may neutral may look grey after using a grey card but the colours depending if they line up with the resulting peaks may look incredibly rich or dull.

The resulting "rainbow" would look like this:

Source: https://secure.wikimedia.org/wikipedia/en/wiki/Compact_fluorescent_lamp

Now imagine using that energy saving bulb to take a photo of something bright yellow and gold with say blue sapphires in it. The blue would likely come out beautifully, the yellow and gold very much not so.

The quality of lighting is very important.

 

[HocusPocus]

Thanks everyone for your time and advice!
I bought a WhiBal and it has improved the photos :thumbup:

 

[gsgary]

You need more light on the background to overexpose it about 1 stop above your subject