“I have an issue that may be of interest to some of your readers. I find that LED warm tone bulbs are increasingly prevalent in houses. In my raw files, they often give a persistent and unpleasant orange cast to a room. But unlike incandescent bulbs, the cast is very hard to correct in post. Is that because they are missing parts of the spectrum? I know that bringing in flashes and lights can cure most of these problems, but are there some clever methods of dealing with warm LEDs that don't involve bringing in external light?”
It’s a very interesting question, Andrew. Yes, as LED lighting is becoming increasingly and quickly adopted in North America to replace less efficient incandescent bulbs, the fact remains that like any other light source, they will cause a color cast in our photos. So, let me begin by saying that I’m not a color theory expert so I can’t answer your question about what is or isn’t in the color spectrum from a warm LED light bulb. It’s my guess though, that light is light and that fixing a cast from such a bulb ought to be correctable with the proper use of flash and color conversion gels. Given the heavy volume of shooting that I do every day, I just don’t have the time to use gels. So, I’m hoping that folks in our community who use gels frequently to navigate color temperature differences can give a thoughtful answer to this question.
In terms of your second question, Andrew, I can tell you that prior to outsourcing my editing, one of the things I used to do to handle pesky color casts, was to use the "select color range" tool. It allowed me to simply select the color I wanted to reduce/eliminate. Once selected, I'd open a Hue/Saturation layer and desaturate only that selected color. To find this tool, go to 'Select > Color Range' in Photoshop's main navigation menu; or better yet, here is a brief video from the great Aaron Nace at PHLearn.com on how to use this particular method.
So, have you noticed this same concern in your work when shooting rooms that have “warm” LED bulbs?