It would be great to be able to adjust the color in an image by selecting a neutral point (white or gray), and using that to remove a color cast. Similar to what Photoshop does. I’m willing to bet you could store the adjusted parameters in whatever structure you already store other color adjustments to.
A selection of white balance presets for different kinds of lighting, rather than only have the sliders, would also be helpful, but I’d prioritize the custom setting based on a neutral point, before that.
I’d like to add my vote to this feature.
When you are taking pics at a certain location and use a grey card or any similar tool, you definitely want to pick the correct white balance by clicking on your neutral card.
VERY important for people like me, who say “I shoot RAW, I can fix white balance later!”
I used the “skin tone” white balance feature a lot in Aperture, and it always either nailed the colors, or got very close. I would love if Mylio supported this as well.