As an old photographer/videographer that’s just started to get into UE4 for archviz, I was rather stumped by how Epic deals with color temp in their lighting scenarios. I can only find in the UE4 docs where they rely solely on the PostProcessVolume color temperature/tint sliders to manipulate color temperature. Setting color temp in video is the single most important beginning step and attempting to do so in post is a kludge or disjointed results.
Also, the sliders only work globally and most any natural scene (not talking about games) in the real world has a vast variation of color temp. I’ve done numerous color temp tests over the last few years using Sekonic C-800, Lumu, Illuminati, and xRite iOne spectros that are placed in various parts of a shot and then recorded from sunrise to sunset. It’s amazing how much variation there is based on the time, date, cloud cover, scene type such as open field, buildings (inside/outside), shady woods, etc. Light reflections from a tangent can vastly alter a scene gray reference such that you can never truly get a neutralized white balance on the reference.
Anyway, I’ve been scouring the web researching this aspect of UE4 lighting and have found little discussion on it. So far, this thread is the only one that leads down the road I’m on, that of using reference sources to white balance UE4 lighting. I’ve already written RGB to Kelvin kludges which are semi-useful but only in ‘perfect’ scenes. I’ve experimented with the included colorchecker models in engine content and am working on a process that will allow sampling a neutral reference and adjust the temp/tint values accordingly and getting the neutral reference to balance.
LOR (first post), check out this link as to why color temp seems backwards. Adobe and other RAW conversion softwares has been doing this for years and very few people ever noticed.
Any feedback on this color temp scenario would be greatly appreciated from an old guy wore out from searching useless internet posts. ;0)
Also, in reference to rosegoldslugs BP for calc’ing CCT, why don’t you post it on the marketplace? Both videos referenced at your link get an ‘Error loading media: File could not be played’.