Which white balance values would you use for these photos?

snerkler

Ok so now seeing the photos that’s really tricky. With an extreme light source like that I doubt the blue will ever look exact as the reflection of light will be different.
One thing I’d try along with WB is to reduce the yellow/orange saturation (preferably using the colour picker) and then brush back the saturation of the yellow fronts of the train. Unfortunately I’m not going to be able to get to my computer until next week.

newbie1

This really is a puzzle.  Capture One has a normalize function where you can pick a color from one image and select where the color should be the same in a second image.  It then adjusts white balance to achieve the match.  This tool gives a huge range of results for the images depending on the color selected and I'm struggling to think of a reason why.  

For example, taking the two images of 67003 the WB adjustments to move from daytime to nightime images are:

railway blue  5000K, -60 tint
grey roof 1060K, -10 tint
67003 number   970K, -10 tint
yellow 5850K, 0 tint
platform 800K 10 tint

This would mean creating masks for the different colors and adjusting each separately.

Does anyone know why this is happening?

snerkler

I’ve never looked into it but I would imagine WB can only ‘correct’ things so far. At the end of the day we’re talking a completely different light source/spectrum reflecting off various surfaces and colours and I would guess that cameras, software, and WB simply can’t adjust for every colour reflected off the various surfaces. Also in extreme situations like this you’re asking a camera/software to produce a colour that isn’t there. Take the blue for example, we know what colour the blue is but the reflected ‘blue’ is different under tungsten and the correct tones of the blue might not be reflected for the camera to capture.

Now this is just me thinking out loud and it could be nonsense, but it’s also why I don’t believe the widely regarded rule that you don’t need to worry about WB settings when shooting raw as you can correct in post. Yes you can most of the time, but in extreme situations I’m not sure you can fully. You can’t get colours that weren’t there/were being ‘masked’ at the time of the shot without some serious photoshop skills.