Today’s Question: When light painting I consistently get a blue color to foliage (greens). I have used a couple of different LED flashlights with similar results. Sometimes I am able to improve, but not completely correct, the issue in post by adjusting white balance and hue using the local adjustment brush in Lightroom Classic. Is there a better light source I can use for painting or some other fix that I can try?
Tim’s Quick Answer: I would recommend either finding a flashlight that can provide a warmer (more yellow to orange) color, or to make use of a colored gel of your LED flashlight.
More Detail: Many LED lights have a relatively neutral to blue color cast, often ranging from about 5,000 Kelvin to around 6,500 Kelvin or so. This can introduce a challenging mixed lighting situation when used as an illumination source for photos, such as when using a flashlight as a supplemental light for a light painting effect.
In most cases you’ll find that a somewhat “warmer” light source that has a somewhat yellow to orange color cast will work best. Some LED lights provide a color temperature adjustment, so you can shift between a warmer (more yellow) or cooler (more blue) illumination. You can also find LED lights that emit light with a warmer color cast.
In general I would aim for a light with a color temperature of about 3,000 Kelvin. An incandescent light bulb typically has a color temperature of around 2,400 to 3,000 Kelvin, for example. On the Kelvin scale a higher value is a cooler color appearance, so you definitely want a light with a value below 5,000 Kelvin, and closer to 3,000 Kelvin would be preferred.
Keep in mind that you can also use gels, which are typically colored translucent sheets of acetate you can place in front of the light source to shift the color of the light. There are various options available, many of which are designed to be mounted in front of flash units or other lights. You can also get a simple colored gel sheet to fashion your own modifier for the light you’ll be using, such as the option shown here: