Originally Posted by
TMM1982
What's a color reference wheel? lol I'm not a photographer at all. I just want some cool selfies under the water with the sharks. But I'd like to capture the beauty of the water as well.
I've never seen it as a wheel.
The simplest thing is a grey card:
https://en.wikipedia.org/wiki/Gray_card which is just what it sounds like--a piece of gray material. To get greater accuracy there are also color charts:
https://en.wikipedia.org/wiki/Color_chart .
The point of these is to have something in the frame of an exactly known color. If you know the card is 18% gray then you adjust the color balance of the shot (the good editing tools will understand how to figure this with little effort) so that the image of the card really is 18% gray--and thus correcting everything else in the process.
The color targets allow correcting for a greater degree of discrepancies and are quite useful for calibrating color-handling equipment. Take a standard color target and make a scan of it. If the numbers in the scan aren't spot on you know the scanner is off and by how much--you create a color profile for the scanner that corrects for these things. Once your scanner is calibrated you can print a test pattern on your printer and scan it, this will find the discrepancies in the printer and allow the creation of a correction profile for it.