Noob Question: How much of white balance/color issues can be fixed in post/editing/color correction?

Hi all. I have been making youtube videos for a few months now, but am pretty much a total amateur/beginner in terms of editing(besides simple cuts and titles and fades lol) and post/color correction. I’ve been filming myself with iPhone 11 Pro playing piano on a concert stage I have access to. Lighting is out of my control. I filmed for a while with native camera app, then moved to Filmic Pro for more control. Its sometimes been challenging because I often have to try to perform piano pieces on a very high level while also learning/dealing with technical issues as I learn more and more about video. One of the main things when filming that stresses me out and I wish I didn’t have to deal with is trying to get perfect is in-camera white balance before starting recording. Its hard to dial in color temp/tint and then really make sure it looks good not only on a small phone screen, but also since I have to do it trial and error because I cant adjust white balance while sitting in the frame because im doing all of this myself. This just takes a way from the energy and excitement to play my instrument and record.
So far in my learning about all of this, it seems that exposure is more important to get in camera before shooting because its hard to for instance fix something over exposed with crushed highlights in POST. And I’ve figured out what shutter/iso settings I want where I record. But the white balance is just always cruddy. And I really dont want to deal with it while shooting, rather fix it in post later.
Is it possible (if you are experienced, not like me) to fix basically any white balance/color issue in post no matter how its filmed? Very often because of the lighting, my videos come out extremely orange toned and overly pink skin shadows because the lights in the hall are orange/yellow. Can everything like that be fixed and made to look “good” in post if you’re good enough at whatever software you use? if so, then is it not that crucial to NAIL white balance in your camera before while shooting? Should I just stop worrying about it while shooting and just learn and get good at color correction to fix it later?

You do not have to nail WB perfectly in-camera. But you don't want to be too far off. Get a decent-sized sheet of white poster board or something, place it on the piano where you'd be sitting. White balance to that, then shoot.

In post, I get great results from the Balance Color effect. It is easy to access via the Color Shortcut Menu (see image below). And a very basic tutorial on color grading would help. Basically, WB first, then adjust contrast. Majority of the time I find that's all I need with decent shots.
support.apple.com/guide/final-cut-pro/in...olor-ver9e1e9aa2/mac

Kofman wrote:

But the white balance is just always cruddy. And I really dont want to deal with it while shooting, rather fix it in post later.
Is it possible (if you are experienced, not like me) to fix basically any white balance/color issue in post no matter how its filmed? Very often because of the lighting, my videos come out extremely orange toned and overly pink skin shadows because the lights in the hall are orange/yellow.

There are basically two "schools" here. A friend of mine always takes a very accurate WB before shooting. This is considered the professional way among many. But I argue against it. Because unless you are in a completely controlled environment like i.e. a studio, you can only react to existing light sources. In the wild, chances are good that you encounter mixed color temperatures. And you can either embrace that fact and make use of it or desperately try to find the average color temperature for each shot. Which will result in terribly inconsistent colors and moods within a sequence of shots.

My approach is to determine the dominant light source in a location and roughly set the WB accordingly once. If that happens to be Tungsten, I choose 3200°K or simply the light bulb symbol. I try to be in the right ballpark, so to speak.

With that setting, a window appearing in the frame will be read as blue. This can look very ugly, admittedly. There are ways to deal with it. One is the theory behind color contrast, when it helps the overall pithiness of the image and when it does the opposite. You can control this by reframing the motif which often means that you have to reposition yourself until you're satisfied with the balance.

The other way is to avoid mixed temperatures altogether. This seems to be safer, but I just don't like flat lighting and nor do I like flat colors.

Post is where you refine your decisions during shooting. Take away some blue cast in the highlights. Or emphasize it.

There are also two schools regarding the treatment of skintones in post. One says that you have to preserve them at any cost, because they are "memory colors", and because the viewer will judge the correct colors by comparing them with skin, they should always fall on the skintone line in your vectorscope.

The other opinion on that, the one I share, is that yes, indeed, skin color is paramount when it comes to grading. But in reality, skin will always look different in different circumstances, and it will do so in a very characteristic way, proving that the person is alive and there.

kofman wrote: … because of the lighting, – the lights in the hall are orange/yellow. …

sounds maybe a bit brush, but it is called WHITE balance by purpose. Meaning, the available light is 'meant' as white, daylight, dawn, snow, tungsten, whatever.

If the stage is lit with 'effect light' = meant as orange, you're leaving the balancing sector and stand deep in Color Correction et al.

Example: when recording my school plays, our stage is often lit in mono-chromatic LED blue = a pest!! And by no means, you can correct that in post into 'normal' light. And my cheap consumer cams are almost killed (auto exposure can not handle such light/color)

What Axel said: have a look, what the over all situation is, 5Kelvin = blueish daylight or 3Kelvin = orange tungsten … and the rest is 'intentional'.When the colors change wile recording…  then the color change.-

If the light is 'meant' as 'white', hold a grey card into the camera (backside of your music notes), so you have at last a reference…

Karsten Schlüter wrote:

sounds maybe a bit brush, but it is called WHITE balance by purpose. Meaning, the available light is 'meant' as white, daylight, dawn, snow, tungsten, whatever.

The main reason why somebody would want the light to be white is not in order to avoid (i.e.) an orange cast, which is typical for old-fashioned light bulbs (the modern 'warm white' LED lights, the ones you buy in the department store, are rather yellow, but that's a different story).

The reason is that all colors in an image are mixed out of just three colors, with white being RGB completely balanced (= by the same numbers, 255/255/255):

... and if you correct for a cast in post, you effectively add the complementary color and further thin out the spectrum.

Everybody has forgotten to set correct WB at some time, and alt+cmd+b in FCPX can seemingly work wonders. However, unless you didn't record RAW, you are starting your grade with a much limited number of original color values. This particularly affects very nuanced surfaces, like, er, faces. Those tend to look colorized and dull afterwards.

You can deliberately warm up a boring, neutral image (one with a correct and exact WB) in post, but you are limited in your options when your footage looks as if shot through an orange effect filter. So the goal of WB is not to get rid of a mood but to maximize color differentiation.